Happening now: Lawmakers grill Obama officials on Syria

Check back here for the latest updates in our live blog of the Senate hearing

(CNN) - Top Obama administration officials faced tough questions Tuesday as they made their case for a military strike in Syria during their first public congressional hearing on the issue.

Secretary of State John Kerry, Defense Secretary Chuck Hagel, and Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey sat before the Senate Foreign Relations Committee Tuesday afternoon.

The specter of the war in Iraq looms over lawmakers as they make their decision to give the president authorization to use force in another war-torn country. Many members are undecided on how they will vote when Congress officially reconvenes from recess next week.

How will they vote? House | Senate

With both Kerry and Hagel being former senators, they know how to navigate a congressional hearing. The officials have already been on the phone with lawmakers in classified briefings and are scheduled to take part in at least one more hearing this week with the House Foreign Affairs Committee on Wednesday.

Check back here for the latest updates from the hearing.

6:45 p.m. ET - Sen. John McCain, perhaps the Senate's most outspoken voice in favor of military action in Syria, was caught playing poker Tuesday at the hearing.

He senator later explained his poker habit on CNN's "The Situation Room with Wolf Blitzer."

"As much as I like to always listen with rapt attention constantly (to) remarks of my colleagues over a three and a half period, occasionally I get a little bored and so I resorted," he said, chuckling. "But the worst thing about it is I lost thousands of dollars in this game."

He followed up, saying it was only "fake" money.

6:10 p.m ET - The hearing is adjourned, roughly three and a half hours after it started. Members will get a classified briefing on Wednesday.

6:09 p.m. ET - Menendez says they are close to finalizing the resolution for markup on Wednesday.

6:01 p.m. ET - Sen. Ed Markey, who filled Kerry's Senate seat with Kerry left to become secretary of state, is the last senator to question Kerry.

5:50 p.m. ET - Libertarian-leaning Sen. Rand Paul engaged in a somewhat tense back-and-forth with Kerry. The Republican senator from Kentucky argued that the outcomes of a U.S. military strike in Syria are unclear and questioned the officials' certainty that such a strike will hurt Assad and make the region more safe.

"Will the region be more stable or less stable? I think there's a reasonable argument the world may be less stable because of this," Paul argued. He also asked if Israel will be more safe, saying a strike in Syria may spur Hezbollah to attack Israel in retaliation.

Paul said his office gets calls by the thousands and not one person is calling in favor of intervening in Syria.

But Kerry said he knows for sure a strike against Syria would make the world–and the region–more safe.

"I can make it crystal clear to you that Israel will be less safe unless the US takes this action," Kerry said in response. "Iran and Hezbollah are two of the three biggest allies of Assad. Iran and Hezbollah are the two single biggest enemies of Israel. So if Iran and Hezbollah are advantaged by the United States not curbing Assad's use of chemical weapons, there is a much greater likelihood that at some point down the road Hezbollah...will have access to these weapons of mass destruction."

Kerry added that Israel feels quite confident of defending itself if Hezbollah attacks out of retaliation.

"If the United States doesn't do this, senator, is it more or less likely that Assad does it again?" Kerry asked Paul

"I think it's unknown," Paul said.

"Senator, it's not unknown," Kerry interjected. "If the United States of America doesn't hold them accountable on this...it's a guarantee Assad will do this again. I urge you to go the classified briefing and learn that."

Kerry argued that all three of the officials at the meeting understand what it means to go to war. "We don't want to go to war," he said. "The president is asking for the authority to do a limited action that will degrade the capacity of a tyrant who has been using chemical weapons to degrade his own people."

"But by announcing that, you say your goal is not winning," Paul said.

Kerry reiterated the president is not asking to go to war but simply saying we need to take "an action" that will hurt Assad. "I don't consider that going to war in the classic sense of coming to Congress and asking for a declaration of war," he said. "That's not what the president is asking for."

Kerry asked if Dempsey wanted to weigh in.

"No not really, secretary. Thank you for asking," Dempsey said.

5:37 p.m. ET - Kerry says if Congress votes down the president's proposal to take military action in Syria, "it is a guarantee–whether it is with Assad in Syria or nuclear weapons in Iran or nuclear weapons in North Korea–we will have invited a for certain confrontation at some point in time."

Speaking to the parallels with Iraq, the secretary of state said there is a distinction. He said intelligence reports at the time indicated weapons of mass destruction simply existed and "we had a mass invasion" to find those weapons. In Syria, however, not only does the U.S. know that chemical weapons exist, but they have been used multiple times, he said.

5:33 p.m. ET -

5:31 p.m. ET - Sen. Chris Murphy, D-Connecticut, says he hasn't seen this level of public debate since the health care reform debate of 2009-2010. Murphy served in the House before being elected to the Senate in 2012.

5:25 p.m. ET - Sen. John Barrasso, R-Wyoming, asks what the president will do if Congress votes down the resolution. Kerry says they're not even contemplating that scenario right now.

5:23 p.m. ET - Menendez says they're looking forward to the "possibility" of a markup tomorrow of the president's resolution.

5:02 p.m. ET - McCain: "When you tell the enemy you're going to attack them, I'm not to take any time on this, you're going to attack them, they're obviously going to disperse and try to make it harder. I'm looking right here at a AP story report Syria said to be hiding weapons and moving troops. There's even open source reporting that they may be moving some of their assets into the Russian naval base. It's ridiculous to think that it's not wise from a pure military standpoint not to warn the enemy that you're going to attack."

5:02 p.m. ET - Sen. John McCain, R-Arizona, begins his questioning. McCain has been one of the most vocal senators in favor of taking military action in Syria. He jokes to Kerry's wife, Teresa, saying "I apologize for what I'm about to do to John."

5:01 p.m. ET - Hagel is sporting a noticeable bruise on his chin. CNN Pentagon Correspondent Barbara Starr reports the SecDef’s injury was a result of exercising his green thumb.

According to an aide, “Secretary Hagel slightly bruised his chin while doing a little yard work at home over the weekend.”

5 p.m. ET - Sen. Dick Durbin, D-Illinois, asks what's been the response of the Muslim-Arab world to the potential of U.S. military action in Syria. "If this danger to the region is so profound, it seems we should have greater support," he said.

Hagel says he would prefer to discuss that in a classified setting.

Durbin asks about collateral damage. Dempsey says the collateral damage estimate is low, but added that figure doesn't include what damage could be done to regime personnel.

4:55 p.m. ET -

4:52 p.m. ET - Sen. Jeff Flake, R-Arizona, asks if there is evidence that the Assad regime is moving some of its targets as the U.S. waits to take military action.

Dempsey responds, saying "there is evidence, of course, that the regime is acting not only to the delay, but also they were reacting to the very unfortunate leak of military planning."

4:29 p.m. ET - Sen. Ron Johnson, R-Wisconsin, asks if Hezbollah has access to chemical weapons, since it has been cooperating with Assad's regime. Kerry says they need to talk about that in a classified setting.

4:13 p.m. ET - Sen. Marco Rubio, R-Florida, raises the question again of what will happen if Assad weathers the attack and feels emboldened after facing down the most powerful nation in the world.

Kerry said that because the president is only asking for "limited authority" to degrade Assad's current ability to use chemical weapons and not asking for permission to destroy "the entire regime," then Assad "will weather" the attack.

"He will be able to stand up and no doubt he'll try to claim that somehow this is something positive for him," Kerry said. "We believe deeply...that there is no way it will in fact be beneficial for him. That will not translate on the ground."

The secretary of state also tried to clarify again that the president is not proposing–or leaving the door open–to putting troops on the ground.

"I want to emphasize something...This authorization does not contemplate and should not have any allowance for any troop on the ground. What I was doing what hypothesizing on the potential of what might happen at some point in time," Kerry said, referring to a point earlier in the hearing when he said putting troops on the ground would not be taken off the table.

4:09 p.m. ET – A protestor interrupts the hearing, yelling "This nation used white phosphorous in Iraq" as he's escorted out.

4:07 p.m. ET - Sen. Cardin asks why there aren't more countries that are actively joining the U.S. in the potential military operation, in addition to offering verbal support.

Kerry said there is "no definitive list" of countries at this point because the president hasn't decided what action will be carried out. But the bottom line, he adds, is that "we're talking about very specific kinds of capacities that in some cases only the United States of America possesses."

Cardin says that he supports the mission.

4:01 p.m. ET - Sen. Ben Cardin, D-Maryland, says it's "clear that we have to respond" to Syria's use of chemical weapons. However, he thinks the draft resolution from the White House on the proposed mission is too broad and does not explicitly prohibit America troops on the ground. He urged the administration to write a resolution with more narrow language that focuses on the limited strike but doesn't leave "open the door for the introduction of troops."

3:59 p.m. ET - Sen. James Risch, R-Idaho, argued the U.S. could be giving credibility to the Assad regime if U.S. does a limited strike, and then Assad still wins the civil war. Kerry responded saying there's no way Assad will be "better off" following U.S. military action.

"If (Assad) responds, he will invite something far worse...but that doesn't mean the United States is going to war," Kerry said.

3:56 p.m. ET -

3:48 p.m. ET - Sen. Barbara Boxer, D-California, says she'll support a strike but not a blank check. She asks if all the different intelligence agencies came to the same conclusion on chemical weapons being used in Syria.

Kerry says he doesn't know of any "agency that was a dissenter or anybody who had, you know, an alternative theory."

3:43 p.m. ET - Following up on his earlier comments about boots on the ground, Kerry says he doesn't want to give the impression that such a scenario is an option. "Let's shut that door as tightly as we can," he said, adding that he was only thinking of a "hypothetical" situation in which the use of chemical weapons spread.

"There will not be American boots on the ground with respect to the civil war," he said forcefully.

3:31 p.m. ET - Menendez asks whether American boots would be on the ground in Syria. Kerry says he can't take it off the table in case Syria "imploded" or chemical weapons landed in the hands of terrorists.

"I don't want to take off the table an option that might or might not be available to the president of the United States to secure our country," he said.

3:26 p.m. ET: Menendez asks if military action in Syria will make the U.S. more secure or less secure. Kerry responds that it will make the U.S. "unequivocally" more secure. Kerry also argued that the consequences of inaction are greater than action.

3:24 p.m. ET - Chuck Hagel: "There are always risks in taking action, but there are also risks with inaction. The Assad regime, under increasing pressure by the Syrian opposition, could feel empowered to carry out even more devastating chemical weapons attacks. Chemical weapons make no distinction between combatants and innocent civilians, and inflict the worst kind of indiscriminate suffering, as we have recently seen.

A refusal to act would undermine the credibility of America's other security commitments – including the President's commitment to prevent Iran from acquiring a nuclear weapon. The word of the United States must mean something. It is vital currency in foreign relations and international and allied commitments.

Every witness here today – Secretary Kerry, General Dempsey, and myself – has served in uniform, fought in war, and seen its ugly realities up close...We understand that a country faces few decisions as grave as using military force. We are not unaware of the costs and ravages of war. But we also understand that America must protect its people and its national interests. That is our highest responsibility."

McCain, Graham issue tough warnings on Syria dilemma

3:23 p.m. ET -

3:20 p.m. ET - Chuck Hagel: "The Syrian regime's actions risk eroding the nearly century-old international norm against the use of chemical weapons...a norm that has helped protect the United States homeland and American forces operating across the globe from those terrible weapons.
...
The United States must demonstrate through our actions that the use of chemical weapons is unacceptable. The President has made clear that our military objectives in Syria would be to hold the Assad regime accountable, degrade its ability to carry out these kinds of attacks, and deter the regime from further use of chemical weapons."

Hagel: 'We're ready to go' if ordered on Syria chemical weapons

3:17 p.m. ET -

3:15 p.m. ET - After Kerry finished his opening statement, a protester started shouting and was removed from the hearing room. "Launching cruise missiles means another war," she yelled.

3:15 p.m. ET - John Kerry: "This is not the time for armchair isolationism. This is not the time to be spectators to a slaughter. Neither our country nor our conscience can afford the cost of silence.

We have spoken up against unspeakable horror many times in the past. Now we must stand up and act. And we must protect our security, protect our values, and lead the world with conviction that is clear about our responsibility."

3:12 p.m. ET -

3:10 p.m. ET -

3:09 p.m. ET - John Kerry: "As confidently as we know what happened in Damascus on August 21, we know that Assad will read our...silence as an invitation that he can use his weapons with impunity.

And in creating impunity, we will be creating opportunity – the opportunity for other dictators and terrorists to pursue their own weapons of mass destruction, including nuclear weapons."

Obama officials try to sway House Democrats on Syria

3:03 p.m. ET -

2:59 p.m. ET - John Kerry: "I remember Iraq. Secretary Hagel remembers Iraq...We were here for that vote. And so we are especially sensitive, Chuck and I, to never again asking any Member of Congress to take a vote on faulty intelligence. That is why our intelligence community has scrubbed and re-scrubbed the evidence. We have declassified unprecedented amounts of information.

We can tell you beyond any reasonable doubt that our evidence proves the Assad regime prepared this attack...warned its forces to use gas masks. We have physical evidence of where the rockets came from and when. Not one rocket landed in regime-controlled territory. All of them landed in opposition-controlled or contested territory. We have a map, physical evidence, showing every geographical point of impact – and that is concrete."

2:55 p.m. ET - John Kerry: "As we convene for this debate, the world is watching not just to see what we decide. It is watching to see how we make this decision – whether in this dangerous world we can still make our government speak with one voice. They want to know if America will rise to this moment and make a difference."

Kerry: 'Signatures of sarin' found in Syria

2:53 p.m. ET - Ranking member Sen. Bob Corker said he hopes the officials will explain why Syria is important to U.S. national interests and why it matters to the Middle East. He also wants to see the U.S. "continue to carry out the strategy that has been stated, and that is building the capacity of the vetted opposition."

2:49 p.m. ET - Sen. Bob Menendez welcomes Teresa Heinz Kerry, wife of John Kerry, who appeared at the hearing after spending three weeks in a rehabilitation hospital following a seizure in July.

2:48 p.m. ET - Members of the Senate Committee on Foreign Relations:

Democrats

Robert Menendez (Chairman)
Barbara Boxer
Benjamin L. Cardin
Jeanne Shaheen
Christopher Coons
Richard J. Durbin
Tom Udall
Chris Murphy
Tim Kaine
Edward J. Markey

Republicans

Bob Corker (Ranking Member)
James E. Risch
Marco Rubio
Ron Johnson
Jeff Flake
John McCain
John Barrasso
Rand Paul

2:46 p.m. ET - Sen. Bob Menendez: "We are at a crossroads-moment. A precedent will be set either for the unfettered and unpunished use of chemical weapons... or a precedent will be set for the deterrence of the use of such weapons through the limited use of military force that sends a message that the world will not stand down."

2:45 p.m. ET - Sen. Bob Menendez: "We know that chemical weapons personnel from the Syrian Scientific Studies and Research Center – subordinate to the regime’s Ministry of Defense – were operating in the Damascus suburb of ‘Adra from Sunday, August 18th until early in the morning on Wednesday August 21st near an area the regime uses to mix chemical weapons including sarin and human intelligence as well as signal and geospatial intelligence have shown regime activity in the preparation of chemicals prior to the attack, including the distribution and use of gas masks.

We have multiple streams of intelligence that show the regime launched a rocket attack against the Damascus suburbs in the early hours of August 21st and satellite corroboration that the attacks were launched from a regime-controlled area and struck neighborhoods where the chemical attacks reportedly occurred clearly tying the pieces together. That is what we know in terms of who may have deployed these weapons.

READ MORE: What is sarin?

2:43 p.m. ET - Sen. Bob Menendez: "Are we willing to watch a slaughter just because the patrons of that slaughter are willing to use their veto at the UN to allow it to happen so their beneficiary can stay in power?

Are we so tired of war that we are willing to silence our conscience and accept the consequences that will inevitably flow from that silence to our national interests?

We will hear the arguments and the options presented to us today and we will look at the facts as we know them according to the declassified assessment released last Friday that Secretary Kerry so passionately presented to the nation."

2:42 p.m. ET - Sen. Bob Menendez: "This decision will be one of the most difficult any of us will be asked to make. But it is our role as representatives of the American people to make it, to put aside political differences and personal ideologies, forget partisanship and preconceptions, forget the polls, politics, and personal consequences. It is a moment for a profile in courage and to do what one knows is right.

It is our responsibility to evaluate the facts, assess the intelligence we have and then debate the wisdom and scope of a military response fully and publicly, understanding its geopolitical ramifications, and fully aware of the consequences.

At the end of the day, each of us will decide whether to vote for or against a resolution for military action based on our assessment of the facts and our conscience."

2:39 p.m. ET - Chairman Bob Menendez, D-New Jersey, opens up the hearing.

“Let me welcome Secretary Kerry, Secretary Hagel, and Chairman of the Joint Chiefs of Staff, General Dempsey, to the Committee.

We convene this hearing, as we have convened many before, to make one of the most difficult decisions we are tasked to make: the authorization of the use of American military power – this time in Syria – to respond to the horrific chemical attack of August 21st that took the lives of 1,429 Syrians including at least 426 children.

The images of that day were sickening. In my view the world cannot ignore the inhumanity and horror of this act."

2:36 p.m. ET - Secretary of State John Kerry, Defense Secretary Chuck Hagel, and Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey walked in for the hearing.

2:25 p.m. ET - Two new polls on Tuesday indicate that more people oppose rather than favor U.S. military strikes against Syria.

Both surveys were conducted before and after President Obama's Saturday announcement that he would seek Congressional approval.

According to the survey from ABC News/Washington Post, 36% of Americans support military strikes, while 59% oppose. Support for strikes increases to 46% if other countries, such as Great Britain and France, participated.

Separately, a Pew Research Center poll shows that 29% Americans oppose military action, while 48% are against launching strikes.