WASHINGTON — In an attempt to rejuvenate his struggling campaign for the presidency today, Senator McCain will outline his support for the war in Iraq, but political analysts say it is unclear what, if anything, the Arizona Republican could say that will improve his standing in the polls.

A McCain aide said he will seek “to put Iraq in a larger context of a battle for the soul of the Muslim world” and that he will specifically call out Democrats as “representing the easy, foolish choice of surrender and withdrawal.”

After laying the groundwork for a second White House bid for years, Mr. McCain entered the 2008 race as the front-runner for the GOP nomination, but his campaign has stumbled early on. Mayor Giuliani has overtaken him in many polls, and he finished a disappointing third in first-quarter fund raising, behind the former New York mayor and even further behind Mitt Romney, who took in nearly $21 million from outside sources, compared with $12.5 million for Mr. McCain.

Most recently, Mr. McCain has drawn criticism for suggesting last week that parts of Baghdad were safe because he and other members of a congressional delegation were able to tour a prominent market. Others quickly pointed out that they were wearing body armor and were protected by armed soldiers and Apache helicopters, forcing Mr. McCain to say he had misspoken.

The flap highlighted the difficulty that he faces as the most prominent supporter of President Bush’s decision to send more than 20,000 additional troops to Iraq. While both of his Republican rivals also back the plan, Mr. McCain is singularly identified with the “surge,” and his campaign could hinge on its success.

Today’s speech at the Virginia Military Institute, the first of three his campaign has billed as major policy addresses, is unlikely to stem the slump in support for Mr. McCain, the director of the University of Virginia’s Center for Politics, Larry Sabato, said.

“He is stuck with his stance,” Mr. Sabato said. “He’s rolled the dice. He’s going to stand by Bush and hope that the surge works.”

Mr. McCain’s 2008 campaign, he said, is fundamentally different from the one he ran in 2000, when he was the straight-talking Republican maverick going up against the establishment candidate, President Bush. This time around, he is trying to recapture the “Straight-Talk Express” while simultaneously offering himself to Republican activists as the “loyalist standard-bearer for an aggressive, tough foreign policy,” Mr. Sabato said. To that end, Mr. McCain’s campaign yesterday announced he had been endorsed by four former secretaries of state to Republican presidents: Henry Kissinger, Alexander Haig, Lawrence Eagleburger, and George Shultz.

The question is whether he can succeed by doing both. Sticking to his guns on Iraq, despite widespread opposition, could remind voters of the McCain of eight years ago.

“He should be McCain,” the director of the Quinnipiac University Polling Institute, Maurice Carroll, said. “He’s never going to turn the Iraq war into a popular war, but he presumably could get credit for being himself.”

Yet that is exactly where Mr. McCain’s comments about the Bab al-Sharqi market in Baghdad, which were derided by some Iraqis as out of touch with reality, could come back to haunt him, a political science professor at Hunter College, Kenneth Sherrill, said. “I think the problem is he’s done damage to his credibility, and that damage is not limited to Iraq,” Mr. Sherrill said. He added: “It undermines his strength as someone who tells it like it is.”

Mr. McCain’s speech comes amid an ongoing standoff between Democrats in Congress and the White House over funding for the war. In a speech to the American Legion in Virginia, Mr. Bush invited leaders of both major parties for talks at the White House, but he reiterated his position that he would not sign a bill that includes a timetable for the withdrawal of American troops. Democrats reacted with skepticism, suggesting a meeting was pointless if the president was unwilling to negotiate, the Associated Press reported.

Also yesterday, Mr. Romney delivered a foreign policy address at the George Bush Presidential Library Center in Texas, calling for increased spending on national defense and a strengthening of America’s international alliances. The former Massachusetts governor said one of his first moves as president would be to convene a “summit of nations” that would include moderate Islamic states.