By John Whitesides, Political Correspondent WASHINGTON, June 27 (Reuters) - The top Republican White House candidates in 2008 are standing firm against quick troop withdrawals from Iraq -- while trying to distance themselves from an increasingly unpopular President George W. Bush any other way they can. Recent calls for a change in Iraq strategy by senior Republican Sens. Richard Lugar of Indiana and George Voinovich of Ohio reignited congressional debate on the war and could embolden more Republicans to question Bush's approach. But the party's leading presidential contenders back Bush's strategy of sending more U.S. troops to Iraq and have resisted Democratic calls for troop withdrawal timelines. At the same time, they have criticized Bush's war management without directly attacking him. With the exception of Arizona Sen. John McCain, they also have condemned a Senate immigration bill backed by Bush. Republican consultant Dan Schnur said the candidates were walking the same fine line faced by Democrats during the 1998 scandal over then President Bill Clinton's relationship with a White House intern. "Watching Republicans talk about Iraq is like watching Democrats talk about Monica Lewinsky. They concede the obvious but still defend the person," said Schnur, a former McCain aide who is unaffiliated in this campaign. "Everyone agreed Clinton's conduct was horrible and everyone agrees this war has not been managed well," he said. "It gives the Republican candidates a chance to distance themselves from his policy without being negative about the man." Bush's approval rating has hit new lows in national opinion polls, which also show his support dipping but still strong among Republican voters who will decide the party's nominee in the November 2008 election. "Even though support for the president is down pretty significantly among Republicans, it's still at or around 60 to 65 percent -- and those are the hard-core Republican primary voters a candidate needs," pollster John Zogby said. The dilemma is compounded because the party's eventual nominee will need to broaden his appeal for a general election campaign and make the case he can change the country -- without pushing away the party's core conservative supporters. BUSH OPPOSED ON IMMIGRATION The Republican insurrection over immigration, which has pitted conservatives against Bush and key allies like McCain, has given candidates an opening to prove their independence without alienating primary voters, analysts said. Leading contenders like former New York Mayor Rudy Giuliani and former Massachusetts Gov. Mitt Romney have criticized the Senate proposal, which conservative opponents say amounts to an amnesty for 12 million illegal immigrants. Giuliani leads national polls in the Republican race and Romney leads polls in crucial early voting states like Iowa and New Hampshire. Without mentioning Bush by name, both candidates also have made recent statements questioning the direction of the country. "It's on a course right now that's just not quite right," Romney was quoted by The Politico newspaper as telling donors at a recent Fenway Park campaign event in Boston. Republican candidates, who frequently pay homage to former President Ronald Reagan, rarely mention Bush on the campaign trail. In contrast, criticism of the president's leadership is often the centerpiece of Democratic political rallies. Texas Rep. Ron Paul, a libertarian and longshot White House contender, is the only Republican candidate to openly oppose Bush's war policies. But a September report on the war's progress by Iraq commander Gen. David Petraeus could give presidential candidates and vulnerable Republicans facing re-election next year the political backing they need to criticize the war. "Republicans know they can't go into this election supporting the war in Iraq," Zogby said. "Something has to be done for them to give them cover."
