What do you do if you are a conservative in a party whose brand has become synonymous with nastiness, xenophobia, homo-phobia, narcissism and incompetence? You could ask William Hague that question. Or Iain Duncan Smith. Or Michael Howard. Or you could ask David Cameron. And it appears that the Republican nominee for the presidency, John McCain – at least metaphorically – has.

As McCain repositions himself as a centrist independent for the election, it is very hard not to think of the Tory struggle these past 10 years. In fact, it’s helpful to think of McCain’s attempt to reach to the centre of American politics as Cameronism Americanised. Or, to coin a phrase: McCameronism.

Cameron, of course, has one huge advantage over McCain – and not just the hair. The bad memories of the last years of Tory rule have diminished over the past decade and even come to contaminate the other party, Labour.

McCain has no such luxury. The Republican brand has rarely been this weak and guilt by association with it this strong.

Gallup’s polling shows that George W Bush is now more damaging to McCain than the firebrand pastor Jere-miah Wright is to Barack Obama. On broader, more stable polling measurements, you will find a historic low in the numbers of people identifying as Republicans and a historically high lead for Democrats of about 10%.

To put this in perspective the Democrats’ lead on the eve of the 2006 election, when Republicans were routed in the Congress, was 6%.

We’re talking landslide potential here: and many are now predicting a Democratic majority in the next House of Representatives of about 70 and a majority of 10 in the Senate. In the younger generation, the Republican brand is even less popular. Last Tuesday saw the third congressional by-election in a very safe Republican seat go to the Democrats – this time in northern Mississippi, no less. For good measure, an all-time record of 82% of Americans believe the country is on the “wrong track”.

Into this brutal landscape for a Republican McCain has already done several clear things to differentiate himself from his party’s brand.

The first should be familiar to those who have studied the Tory modernis-ers in Britain. McCain went green.

Last week, he unveiled his own support for a “cap-and-trade” carbon emissions regime just a mite less onerous than Obama’s. Implicitly, he scorched the current president’s en-vironmental record by saying that he would not stand by and let America do nothing while issues such as climate change dominate global discussion.

“We stand warned by serious and credible scientists across the world that time is short and the dangers are great,” McCain intoned. “The most relevant question now is whether our own government is equal to the challenge.”

He maintained his opposition to drilling for oil in the protected part of Alaska. He went on a green photo-opportunity in the Mountain West. And he even unveiled a green McCain logo, with a recycling symbol on it.

Next, he pledged last Thursday to bring most of the troops home from Iraq by the end of his first term. In a slightly strange speech premised on the notion of McCain looking back on his first (and only?) term, McCain predicted: “By January 2013 America has welcomed home most of the service-men and women who have sacrificed terribly so that America might be secure in her freedom . . . The United States maintains a military presence there, but a much smaller one, and it does not play a direct combat role.”

What he’s clearly trying to do is construct the autumn debate so that the major difference between the two candidates is not who will get the US out of Iraq, but the manner in which each will do it. Good luck.

McCain has also broken with Republican orthodoxy on two central questions: immigration reform, where he is much closer to the Democrats than to his own party base; and torture, where he has pledged to end the current administration’s violation of common article 3 of the Geneva conventions.

On both these issues he is not just alienating the core base of the Republican party, he is enraging it. And part of that rage comes from a fearful sense that McCain’s Cameronite message could work.

Last week Rush Limbaugh, the right-wing talkshow host, bemoaned: “It’s entirely possible this newly constituted Republican party, which stands for nothing but liberalism lite, might end up winning because a lot of the country might look at this socialist bunch the Democrats are offering and say pooey, and want no part of it, and then where are we?”

Well, you’re with a Republican president intent on remaking the Republican brand: that’s where you are. And it doesn’t make everyone happy. One of the more ferocious Republican blog-gers on the web, Michelle Malkin, summed up a lot of the base feelings: “I don’t want a Republican presidential nominee who sneers about profits like Ralph Nader. I don’t want a Republican presidential nominee who talks and walks like Al Gore. And as I’ve said before in response to the annoying McCain platitudes about ‘reaching across the aisle’ and ‘getting things done’ . . . ‘Get things done’ is mindless liberal code for passing legislation and expanding government.”

If this kind of sentiment reminds you of Lord Tebbit on Cameron, you’re not far off. The difference is that McCain is the elder statesman and Malkin a whippersnapper.

McCain also understands that part of the Republican problem, especially after Hurricane Katrina, is a widespread notion that it is unconnected to many minority voters, especially African-Americans and Hispanics who make up a growing segment of the voting public.

McCain’s long record with Latinos in his home border state of Arizona gives him an opening here. But he knows he has his work cut out for him. So he also did a classic Cameron gambit recently and spent a week touring parts of “forgotten America”, parts where poverty and racial diversity are the norm.

As Tim Pawlenty, the young Republican governor of Minnesota, noted recently: “The country is changing. The Republican party has to have a message that reflects faces and voices of America. We have to do a better job of recruiting women candidates, candidates of colour and diversity.” Pawlenty, by the way, is often spoken of as a vice-presidential pick for McCain.

Yes, Bush paid lip service to diversity and had two African-American secretaries of state. But his immigration plans collapsed after a revolt in his own party, his antigay positions alienated him from the more inclusive younger generation and Hurricane Katrina and those scenes from New Orleans killed his small gains among black voters.

McCain, moreover, is up against more than Bush was four years ago. He will almost certainly have to confront a black Democratic rival whose closest competitor was a woman. The danger is that disaffection with the Republican brand and a huge wave of young, black and Latino voters could become an electoral tsunami crushing the Republicans in November.

So McCameronism is the new product. And McCain, who was one of the few American Republicans to visit the young Tory leader before he was riding high in the polls, is trying to follow the British lead.

It’s harder. McCain hasn’t even begun to overhaul his party – and will have to run for office by both disowning and coopting it at the same time, not an easy task.

If elected, he will have to govern as an independent, triangulating away from what is almost certain to be a large Democratic majority in both Houses of Congress.

But this is the only chance he’ll ever get. And if he has to learn a thing or two from a British fortysomething, he’s happy to do so. From Thatcher, we got Reagan. From Cameron, McCain? Unforeseen, for sure. But so has almost everything important that has happened in this election so far.

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