US Sen. Joseph Lieberman arrived in South Florida this week for several days of campaigning on behalf of John McCain, the candidate he argues is best equipped to lead the battle against Islamic radicalism. In an appearance here Wednesday before the Republican Jewish Coalition, Lieberman (I-Conn.) touted McCain's strong national security credentials, his steadfast support for Israel and his record as an independent-minded maverick unafraid to stand up for his beliefs even when they run afoul of public opinion. "From the moment the next president steps into the Oval Office, he or she will face life-or-death decisions in this war," Lieberman said. "That's why we need a president who is ready to be commander-in-chief from day one, a president who won't need any on-the-job training. John McCain is that candidate and will be that president." Lieberman fully acknowledged the irony that he, a former Democrat who barely seven years ago was his party's nominee for the vice presidency, is now stumping for a Republican candidate. Indeed, he sought to turn his crossing of party lines into a virtue, stressing that he feels so deeply about McCain's ability to confront Islamic terrorism that he is willing to overlook the many differences the two lawmakers share on social issues, from abortion to Supreme Court nominations. On Wednesday, he quoted Arthur Vandenberg, the Michigan Republican and former isolationist who famously converted to internationalism toward the end of World War II out of concern for the rising tide of Soviet communism. "Politics, partisan politics particularly, must end at the water's edge," Lieberman said, referencing Vandenberg. "The enemies we have don't distinguish between Republicans and Democrats. They hate us all and our way of life," Lieberman said. "I believe that deeply." Since his endorsement of McCain, Lieberman has emerged as the campaign's de-facto emissary to the Jews, particularly in South Florida, where the community's significant numbers and high turnout for elections could be crucial in a close race. The Florida primary is slated for Jan. 29. On Thursday he was scheduled to appear at a Chabad luncheon in Fort Lauderdale and address the annual gala fund-raiser of the Jewish Federation of Broward County. Before arriving in the state, Lieberman spoke at an Orthodox synagogue in Charleston, S.C. In what appeared to be a gentle swipe at former New York City Mayor Rudy Giuliani, who is also in hot pursuit of Jewish votes in Florida - a state that is crucial to his presidential hopes - Lieberman stressed Wednesday that McCain is the most electable candidate in the Republican field. "As I was taught very early by a mentor in Connecticut, you can't get anything done for your state or your country unless you get elected," Lieberman said. "In the end, the question is who can get elected. Senator McCain is clearly the most electable Republican candidate for president and that, in the end, has to matter."