Senator McCain’s latest additions to his 2008 presidential campaign team — a veteran of Democrat Howard Dean’s presidential campaign, and a former Bush administration State Department official — are setting Washington to speculating about the ideological direction Mr. McCain’s run for the White House might take.

The new pledges of support for the Arizona Republican came from an Internet guru best known for Governor Dean’s upstart presidential campaign in 2004, Nicholas Mele, and from a former State Department official and veteran trade negotiator, Robert Zoellick.

The news of both decisions come in a week in which Mr. McCain first was reported by the New York Times to have Richard Armitage, Brent Scowcroft, and Colin Powell among his foreign policy advisers, prompting some raised eyebrows among neoconservatives who had viewed Mr. McCain as more sympathetic to them. Later in the week, Mr. McCain sharply criticized the Bush administration for having, he alleged, suggested that victory in Iraq would be easier than it was.

Both Messrs. Mele and Zoellick confirmed that they plan to advise Mr. McCain as he explores the possibility of a presidential bid.

“I have long admired Sen. McCain’s work on campaign finance reform and his independent streak,” Mr. Mele, who is known as Nicco, wrote yesterday on his blog. “This is a personal decision for me based on my own first-hand experience. I like Sen. McCain—I think he should be president!”

Word of Mr. Mele’s move touched off considerable debate in the blogosphere, particularly because of his prior ties to Dr. Dean, who was a darling of the Democratic Party’s left wing in the last race and who is now chairman of the Democratic National Committee.

A Democratic consultant who managed the Dean campaign, Joseph Trippi, said his former colleague in the Dean camp was never a die-hard leftist. “Nicco is not driven ideologically. He’s not conservative or liberal. He’s more sort of a ground-up grassroots guy who believes we’ve got to have total reform of the political system and the role of money in it,” Mr. Trippi said.

Still, the announcement met with skepticism from some conservatives. “‘Personnel,’ as Morton Blackwell likes to say, ‘is policy,'” a writer for the blog of Human Events magazine, Matthew Lewis, observed.

At RedState.com, Erick Ericson said the affiliation with Mr. Mele signaled that Mr. McCain might attempt an independent bid for the White House. “At the end of the day, John McCain and his newfound friends on the left might win the media primary, but they will have a hard time winning a Republican primary,” Mr. Ericson wrote.

The news about Mr. Mele drew a more vitriolic reaction from left-leaning commentators. A prominent Web activist who goes by the online name Atrios, Duncan Black, reacted to the news by tarring the McCain devotee with a British vulgarity similar to “jerk.”

A writer for the Nation magazine’s blog, Ari Berman, said Mr. Mele may wind up disenchanted. “Mele and other Democrats tempted to follow his lead should realize that the straight talking McCain of 2000 is not the Bush-coddling McCain who wants to win in 2008,” Mr. Berman wrote.

A top aide to Mr. McCain, John Weaver, denied any ideological wobble on the senator’s part and stressed that Mr. Mele was not taking a policy role. “He’s buying into the senator’s philosophy, not the other way around, obviously,” Mr. Weaver said.

Mr. Mele’s Web site went offline for a time yesterday afternoon, apparently as a result of a flood of traffic. The Internet marketing firm he runs, which promotes clients such as the trial lawyers’ lobby, Air America, and the Campaign for America’s Future, issued a statement reaffirming its commitment to “progressive”causes. “We do not now, nor will we in the future, support Republican campaigns,” the company, EchoDitto, said.

Mr. Zoellick, 53, who stepped down as deputy secretary of State last month, said he was approached as part of an effort by Mr. McCain’s aides to bolster the senator’s stable of advisers on economic issues. “They’re doing an excellent job of seeing people that support Senator McCain and starting to put together information groups on economic and domestic policy, in particular,” the veteran diplomat told The New York Sun. “I’ve been through a number of these,” Mr. Zoellick said, describing roles advising Republican presidential campaigns in 1988 and 2000. “Their thought is I can try to help them across the board.”

On foreign policy issues, Mr. Zoellick is not clearly associated with either the neoconservative or realist camps. He signed a landmark 1998 letter in which a neoconservative group known as the Project for the New American Century urged President Clinton to push for Saddam Hussein’s ouster.

However, under Presidents Reagan and George H.W. Bush, Mr. Zoellick served for years as top aide to James Baker III, a so-called realist who has sometimes been a lightning rod for neoconservative criticism.

An essay Mr. Zoellick wrote for Foreign Affairs in 2000 spoke of America as a pre-eminent force in the world, but also emphasized the usefulness of “building and sustaining coalitions and alliances.”

Mr. Mele’s decision was first reported on the Web site of a Washington political newsletter, the Hotline. Mr. Zoellick’s pledge to advise Mr. McCain was disclosed online by Time Magazine.