Washington (CNN) - As the Ukrainian military readied for a possible widespread Russian incursion into its Crimea region, Republican lawmakers urged President Barack Obama to take action to prevent the situation from descending into chaos.
In a statement released Saturday, Sen. John McCain, R-Arizona, said he is "deeply concerned" Russia's presence in Ukraine could expand if the President does not outline consequences for President Vladimir Putin's regime.
"President Obama said that Russia would face 'costs' if it intervened militarily in Ukraine," McCain said. "It is now essential for the President to articulate exactly what those costs will be and to take steps urgently to impose them."
On Saturday, Obama spoke by phone with Putin for 90 minutes, and expressed "his deep concern over Russia's clear violation of Ukrainian sovereignty and territorial integrity," according to a statement released by the White House.
Putin requested and received unanimous approval from Russia's upper house of Parliament to send Russian military forces into Crimea to secure the lives of Russian citizens and military personnel he says have been threatened.
Despite a flurry of activity Saturday in Washington, including a confab of the President's national security team, the White House remained mum on how the United States intended to respond to the situation.
A member of the Senate Armed Services and Senate Foreign Relations Committee, McCain called Russia's actions an "ongoing military intervention" that would only worsen in severity so long as the President and the international community sit on the sidelines.
"Every moment the United States and our allies fail to respond sends the signal to President Putin that he can be even more ambitious and aggressive in his military intervention in Ukraine," McCain said.
McCain, the President's former Republican rival in the 2008 presidential election, has routinely criticized the Obama administration's foreign policy, painting the White House as rudderless in their dealings with other nations.
In a February interview with a Phoenix radio station, the Arizona senator branded Obama as "the most naive president in history," sentiments he echoed Saturday.
"None of us should be under any illusion about what President Putin is capable of doing in Ukraine," McCain said.
President's foreign policy a favorite GOP target
McCain's pronouncement was one of a growing number of GOP statements demanding the White House act on Ukraine, but only the latest in a long line of Republicans taking aim at the president's foreign policy.
Now in his sixth year as commander in chief, the President has tried, mostly to no avail, to quiet a constant din of skeptics questioning his overseas priorities. His moves to end the war in Iraq and draw down the U.S. presence in Afghanistan reflect the Obama administration's evolving policy goals.
But the White House's handling last year of Syria's spiraling civil war renewed questions over whether Washington had abdicated its leadership role in world affairs and Obama was content to "lead from behind."
At January's World Economic Forum in Davos, Switzerland, Secretary of State John Kerry protested that reports of America's demise as a foreign policy power were greatly exaggerated.
"I am perplexed by claims that I occasionally hear that somehow America is disengaging from the world - this myth that we are pulling back or giving up or standing down," Kerry said. "I want to make it clear today that nothing could be further from the truth."
But a September CNN/ORC reflects a disconnect between the administration's words and the public's perceptions; only four in 10 Americans approved of the President's handling of foreign policy, the lowest level ever recorded on that issue in CNN polling.
According to a CBS News/New York Times poll released Wednesday, Obama's ratings on foreign affairs have yet to recover in the face of a new crisis. The survey found 39% of Americans currently approve of his approach to foreign policy.
Rubio: Time to punish Russia
The President's vulnerability on the issue has sparked a flurry of criticism, including from a potential Republican 2016 presidential contender. In an op-ed published Saturday morning in Politico, Sen. Marco Rubio, R-Florida, enumerated eight steps he believes Obama "must take to punish Russia" for encroaching on Ukraine's sovereign territory. Rubio framed the ongoing crisis as "a critical moment in world history."
"The credibility of the alliances and security assurances that have preserved the international order is at stake," Rubio said in the piece. "If Putin's illegal actions are allowed to stand unpunished, it will usher in a dark and dangerous era in world affairs."
"The President must now accept that the only way to deal with tyrants like Vladimir Putin is with a clear understanding that they can't be trusted and that only decisive action will deter their provocative moves," Rubio wrote.
Though Rubio and other 2016 hopefuls might use Ukraine's plight to bolster their foreign policy bona fides, their calls for decisive action have limited real world recourse.
As the rhetoric on both sides of the aisle escalates, the United States and its European allies have limited options - short of engaging the military - for impacting the situation on the ground in Ukraine.
The lack of avenues available to the administration did not silence the GOP's rancor.
Ranking Republican on the Senate Foreign Relations Committee, Sen. Bob Corker, R-Tennessee, said Obama must "lead a meaningful, unified response" to the crisis, something he has thus far failed to do.
"The Russian government has felt free to intervene militarily in Ukraine because the United States," Corker said in a statement, "along with Europe, has failed to make clear there would be serious, potentially irreparable consequences to such action."
Corker said Congress would consider targeted sanctions against Russia but pressed again for immediate action from the White House.
"The United States and our European allies should immediately bring to bear all elements of our collective economic strength to stop Russian advances in Ukraine," he said.
Warning about standing on the sideline
The chairman of the House Armed Services Committee, Buck McKeon, R-California, painted the administration's hesitance to intervene in even starker terms.
"History judges perpetrators of these actions poorly, as it does those who stand idly by," McKeon said in a statement. "Our response should demonstrate the U.S. stands by its friends against bullies."
Calling Putin a would-be empire builder whose actions are a "throwback" to the Cold War, McKeon continued, saying Russia's military maneuvering has "violated the freedom of all Ukrainians."
Rep. Tom Cotton, R-Arkansas, gave perhaps the most cutting critique of the Obama administration's response.
"Emboldened by President Obama's trembling inaction, Vladimir Putin has invaded the Crimea region of Ukraine," Cotton, who sits on the House Committee on Foreign Affairs, said in a statement.
Cotton, the GOP challenger for incumbent Democrat Mark Pryor's senate seat, sketched out a series of potential actions President Obama could take against Russia should they not withdraw from the Crimea: revoking travel visas, freezing assets of senior Russian officials, rescheduling the G-8 summit in Sochi, suspending Russia from the forum of governments, and recalling the U.S. ambassador to Russia.
"Putin must be punished for his outlaw actions and the Russian people and elites must recognize they will pay a price for them," Cotton said.
Still, the Arkansas lawmaker believes the fate of Ukraine hangs in the balance.
"The hours ahead will decide whether this invasion of Crimea is repelled or expanded to the whole of Ukraine, and whether the West finally confronts Putin or again blinks in disgrace," he said.