(CNN)— Connecticut Senator Joe Lieberman echoed presumptive nominee John McCain's increasing criticism of Barack Obama’s willingness to meet with Iranian President Mahmoud Ahmadinejad.

In an interview with CNN's Wolf Blitzer Friday, the Democrat turned independent said he didn’t question Obama’s commitment when it comes to the Middle East, but said the Illinois senator's failure to set pre-conditions on the meeting shows inexperience, and “not only gives prestige [to Ahmedinajad], but threatens our allies in the region.”

“One of John’s strengths is that our allies and friends will trust him and our enemies will fear him," said Lieberman, who has backed the Arizona senator's presidential bid. "McCain knows when to be tough and when to be soft.”

Lieberman said the Democratic race wasn't over yet — but he said it was pretty clear to him that Obama will be the nominee, adding “it will be a tough [general election] campaign.”

Sen Lieberman has traveled with McCain on the campaign trail.

(CNN) — Sen. Joe Lieberman — the Democratic vice presidential nominee in 2000 — is willing to address the Republican National Convention if it will help Sen. John McCain win in November, his office confirms to CNN.

In an interview published Tuesday night, the independent Connecticut senator told The Hill newspaper that “If Sen. McCain, who I support so strongly, asked me to do it, if he thinks it will help him, I will.”

Lieberman, who lost his Democratic superdelegate status when he was re-elected to the Senate as an independent, endorsed the Arizona senator earlier this year and has actively campaigned for the presumptive GOP nominee.

McCain has not yet asked Lieberman if he would address the Republican nominating convention in September.

Lieberman and McCain recently went on a legislative factfinding trip to the Middle East including a visit to the Western Wall in Israel.

(CNN) — Sen. Joseph Lieberman, I-Connecticut, compared presumptive Republican nominee John McCain to a surprising figure on Sunday — Democratic icon John F. Kennedy.

“I'm a Democrat who came to the party in the era of President John F. Kennedy,” Lieberman told George Stephanopoulos on ABC’s “This Week. ”It's a strange turn of the road when I find among the candidates running this year that the one, in my opinion, closest to the Kennedy legacy, the John F. Kennedy legacy, is John S. McCain.”

The Democrat-turned Independent endorsed McCain in early February, surprising many in the Democratic party. Lieberman, who ran with Al Gore on the Democratic presidential ticket eight years ago, insisted that his views have remained consistent while the Democratic Party changed.

“The Democratic Party today was not the party it was in 2000. It's been effectively taken over by a small group on the left of the party that is protectionist, isolationist and basically… very, very hyperpartisan. So it pains me,” he said.

A staunch supporter of the Iraq war, Lieberman recently traveled to Baghdad with McCain and Sen. Lindsey Graham, R-South Carolina. Though he commended Hillary Clinton for her vote on declaring the Iranian Revolutionary Guard Corps a terrorist group, he slammed both Democratic presidential candidates on their foreign policy positions.

“The Democratic candidates have spent most of their time attacking the war in Iraq… they've honestly not done anything substantial to advance our cause in Afghanistan or against Al Qaeda.”

–CNN's Peter Lanier

Lieberman endorsed McCain last month.

WASHINGTON (CNN) – Democrat turned-Independent Joe Lieberman is set to hit the campaign trail in New Hampshire with Republican John McCain Wednesday, six days before the Granite State holds the nation's first 2008 presidential primary.

Both men will appear together in Derry for a meet-and-greet before Lieberman attends events on the Arizona senator's behalf in Keene, Nashua, Concord, Dover, and Portsmouth.

The Connecticut senator officially endorsed McCain two weeks ago, saying then, "no one should let party lines be a barrier to choosing the person we believe is best qualified to lead our nation forward."

– CNN Ticker Producer Alexander Mooney

WASHINGTON (CNN) — GOP presidential hopeful Sen. John McCain picked up another endorsement Monday. This one came from across the aisle – from a fellow senator who, like McCain, has been known to do the unconventional on occasion. Mary Snow has that report.

Senior Political Analyst Bill Schneider takes a look at the latest dust-up between GOP rivals Mitt Romney and Mike Huckabee. This time the two are trading barbs over U.S. foreign policy. Schneider reports on what the greater implications of the foreign policy squabble may be in the GOP presidential nomination race.

Former president Bill Clinton has stepped up his attacks of Sen. Barack Obama, one of his wife's main rivals for the Democratic nomination. Suzanne Malveaux reports on the latest round of (Bill) Clinton vs. Obama.

Plus, Candy Crowley, Jack Cafferty, and Gloria Borger discuss Mike Huckabee's latest ad and Huckabee's recent critique of the Bush administration's foreign policy.

Click here to subscribe to The Best Political Podcast

–CNN Associate Producer Martina Stewart

Lieberman is co-hosting a fundraiser for Republican Sen. Susan Collins Thursday.

Washington (CNN) - A fundraiser Thursday night for Sen. Susan Collins, R-Maine, is drawing heat from liberals due in large part to the event’s co-host: Sen. Joseph Lieberman, I-Connecticut.

In an e-mail sent to supporters, the anti-war group MoveOn.org called tonight’s event “absurd,” labeling it “Joe Lieberman’s Republican fundraiser.” The event, which will be held in Washington, is being co-hosted by Lieberman and Republican Sen. Arlen Specter of Pennsylvania.

MoveOn.org is working to counter Lieberman’s efforts by raising money for Collins’ 2008 Senate opponent, Democratic congressman Tom Allen. As of Thursday afternoon, MoveOn had raised over $200,000 for Allen in just over 48 hours. Allen’s campaign said it welcomed the support.

Over the past several years, Lieberman’s support for the war in Iraq has made him a marked man among liberal bloggers. His reputation on the Web bottomed out last year during his contentious Senate race with millionaire businessman Ned Lamont, an anti-war Democrat. Thanks largely to the support of prominent liberal bloggers, Lamont upset Lieberman in the Connecticut Democratic primary last August. Lieberman then switched his party affiliation to Independent and was re-elected to the Senate in November.

Collins endorsed Lieberman at the time, and the two senators have worked closely together on the Senate Homeland Security and Governmental Affairs committees.

“Senator Lieberman is very pleased to support Senator Collins because she is an extremely effective senator who works in a bi-partisan fashion to get things done,” said Lieberman spokesperson Marshall Wittman. “Senator Lieberman strongly believes that the American people want progress before partisanship.”

A spokesperson for Collins called Allen an “extreme party loyalist” and dismissed the MoveOn fundraising effort.

“The event that Senators Specter and Lieberman are hosting for Senator Collins tonight strikes a blow at those who thrive on base-driven politics and hyper-partisanship,” said Collins spokesperson Jen Burita in an email. “Senator Collins is proud to have support of Senators Specter and Lieberman and looks forward to tonight’s event.”

– CNN Associate Producer Peter Hamby