It may seem early to see Republican presidential aspirants butting heads, but Senator McCain of Arizona and Governor Romney of Massachusetts are already fighting a proxy battle in the state that both see as pivotal to the 2008 GOP presidential nomination.

Michigan plays a key role in both men’s plans. Mr. McCain had a surprise victory there over George W. Bush in 2000. Mr. Romney’s father, George, was a revered three-term governor of Michigan.

As one Michigan consultant put it, “If there are three tickets out of Iowa, two out of New Hampshire, and the two fight like cats and dogs in South Carolina, Michigan will either ratify those results or turn the race upside down. If McCain were to lose Michigan, he would fall to pieces. And if Romney can’t win in Michigan, people will ask if he can win anywhere.”

One front in the McCain-Romney fight centers on the state’s current Republican Party chairman, Saul Anuzis.

The day after this year’s elections, Mr. Anuzis wrote a letter to state Republicans declaring, “There is a campaign underway to ‘find’ a new Chairman. Just for your information, they are planning to have Dave Dishaw replace me.”

Some Michiganders close to Mr. McCain sought to see Mr. Anuzis replaced at the next state party convention in February after this year’s disappointing elections, but after several weeks of behind-the-scenes arm-twisting, it appears that effort has fallen short.

“I don’t think there’s any fight going on, that’s sort of been settled,” said the state’s Republican National Committeeman, Charles Yob, who is a McCain ally. “You have election that goes bad, there are a lot of dos and don’ts. But it’s been worked out.”

The editor of the conservative group blog RedState, Erick Erickson, who is a fan of Mr. Anuzis, contends that McCain allies launched a whisper campaign against the chairman, and that several individuals joined RedState using pseudonyms to post blog entries criticizing the state chairman — two of them using an identical IP address (the same computer).

McCain-affiliated Michigan Republicans suggested that Mr. Anuzis is a secret Romney backer because the consulting firm he founded, Sterling Corporation, signed on to work with Mr. Romney’s political action committee. Mr. Anuzis insisted he is neutral.

One associate of Mr. Anuzis said the speculation of Romney favoritism is off base, suggesting, “If Saul had his way, he would appoint Newt Gingrich president tomorrow.”

To Mr. Anuzis’ critics, 2006 was the state party’s Little Big Horn. Despite a faltering state economy, Governor Granholm, a Democrat won reelection by 14 percentage points and Senator Stabenow was reelected by 16 percentage points. Gubernatorial candidate Richard DeVos lost decisively even in Grand Rapids, a traditionally Republican-leaning city where his philanthropic family’s name dots the skyline.

But it’s an open question as to how much of this can be laid at Anuzis’ feet in a year where Republicans dramatically underperformed nationwide. Incumbent Republican senators were shellacked in Ohio and Pennsylvania; in Minnesota, Rep. Mark Kennedy, once thought a serious contender for that state’s open Senate seat, lost by 20 percentage points.

Also key to the McCain-Romney battle is what type of primary the Republicans will have in 2008. Mr. Anuzis recently backed what is described as a “semi-open primary” where any voters, not just registered Republicans, can participate in the Republican presidential contest as long as they choose a Republican ballot before entering the voting booth. In most states with this sort of primary, the voters’ choice of party is recorded, and the state parties can access those records.

Mr. McCain’s 2000 victory came in an open primary, with the support of many Independents and likely some Democrats who preferred him to Mr. Bush. There was little interest in that years’ Democratic primary, as Vice President Gore was well on his way to drubbing Senator Bradley. With competitive primaries in both parties in 2008, there may be fewer crossover voters, presuming Michigan Republicans keep their primary on the same day as the Democrats’.

“We wanted a more open primary,” Mr. Yob said. “We don’t want Democrats voting in it, but we want independents, and we want it on the same day so that people can come in and vote in the primary they prefer. We want independents to support our party, and so we want them to have a choice in who leads it.”

But some in the state wonder which Republican will benefit from a semi-open primary.

“The McCain camp is acting like the generals fighting the last war,” said one veteran Michigan political professional. “What worked for them six years ago probably wouldn’t work in 2008. If they had as wide open a primary as 2000, if anybody might benefit it might be Giuliani. The circumstances in 2000 made for a uniquely McCain-friendly phenomenon… it was more than a little unusual to see the highest Republican turnout in Detroit history.”

It may seem a bit early for sharp elbows between primary competitors, but Mr. Yob says there is precedent, with successful candidates such as Governor Engler and Senator Abraham starting two years early. “It’s not a good thing, but it’s a must,” Mr. Yob said. “And 2008 is going to be a wild year.”