He was viewed as America’s most admired politician and the frontrunner for the Republican presidential nomination. That was last year. This week — with three new polls all showing him sinking fast and his campaign bracing for another weak fundraising report on June 30 — even his supporters admit that John McCain is in trouble.

These are still early days in what is the longest and most expensive presidential race in history. But as things stand this weekend in the wildly unpredictable Republican contest, three things are clear: Fred Thompson, the Law & Order star and former senator, even before he has formally declared, has shaken up the field so much that he is already nearing the top of some polls; Rudy Giuliani, the former Mayor of New York, still leads, but is leaking support and looks far from invincible; and Mr McCain’s dismal year has just got worse.

With his aides already conceding that his second-quarter fundraising, like his first, will fall well short of his main Republican rivals, Mr McCain was faced with three polls in the past 72 hours showing that he has slumped to a lowly third place among Republican primary voters in less than a month.

He is now tied roughly with Mitt Romney, the former Massachusetts governor, at about 12 per cent in national primary polls, with Mr Giuliani and Mr Thompson in the high 20s. Mr Romney, meanwhile, after a massive television campaign, leads among Republicans in the crucial early states of Iowa and New Hampshire.

After his maverick primary challenge against President Bush in 2000 — the “Straight Talk Express” that turned him into a national figure — Mr McCain has been stymied consistently this year by several factors, most of which, to his credit, stem from his refusal to bend to the political winds.

He has been a staunch supporter of Mr Bush’s Iraq strategy and, almost alone on Capitol Hill, was calling for a troop surge at least two years ago. Now that he has his wish — an increase in troops that many see as too little, too late — he is hostage to a policy with which he is closely identified but over which he is powerless.

Conservatives, a key constituency in the Republican primary, have always distrusted Mr McCain, even though he has opposed abortion consistently and is a tireless crusader against profligate spending. Many still regard his attempt to unseat the Republican Dauphin in 2000 — Mr Bush — as treachery, and resent his efforts to clean up political funding. He is also 70. If he wins the White House, he would be the oldest man to become president. Although his debate performances have improved greatly in recent weeks, he has had trouble shaking off a perception that he may be a little too short-tempered and elderly to take the helm of a country thirsting for fresh leadership.

What has cost him most in the past month is his co-spon-sorship with the liberal Ted Kennedy of an immigration reform Bill, anathema to conservatives because it seeks to give 12 million illegal immigrants a path to citizenship.

Mr McCain is the toughest of men. He survived five and a half years as a PoW in Vietnam, when he was tortured frequently by his captors. Mr Giuliani could implode. Mr Thompson could fizzle. Mr Romney’s brazen inconsistencies could yet undo him. But so far, it has not been Mr McCain’s year.

Times Recommends

• Gloves off as McCain lands Obama 'lie' jibe
• Anger as terrorist gets bail for IVF
• US hands palace of Saddam back to Iraqis