In my Telegraph column today I look at why so many Conservatives have decided to support Barack Obama rather than John McCain, and I briefly explain my decision to come off the fence and join them.

I never thought the day would come when I would not support a Republican candidate. Ronald Reagan is one of my political inspirations, but he is probably turning in his grave when he sees what has happened to the party he led with so much distinction. It has turned from the Grand Old Party into a narrow religious sect. It has lost its compassion in a desperate rush towards social fundamentalism at the same time as losing all sense of fiscal responsibility.

I had hoped that a Giuliani candidacy would shake the Republican Party out of its trance, but it was not to be. I had then hoped that John McCain might show a vision for America and the world which could stand the test of a presidential campaign. I had hoped his experience and tenacity would provide a launchpad for four years of a very different kind of Republican administration. But McCain has failed in every conceivable way. He has performed poorly in the debates, he is an uninspiring speaker and his vision is as non existent as Gordon Brown's. His policy platform simply doesn't add up and his foreign policy ideas are as unappealing as many of George Bush's. On 30 January I wrote this about the Super Tuesday Republican primaries...

I will support John McCain, albeit incredibly reluctantly. I just don't see the ideas, the optimism, the can-do attitude that I think such a candidate needs.

Nothing has since changed my mind.

And then there is Sarah Palin. As regular readers know, when she was chosen I said she would prove to be an inspired choice or a car crash. The initial evidence leant towards the former. Latterly, though, we have all seen too much evidence of the latter. I defended her against the appalling media onslaught against her, which I found sexist, insulting and worse. I simply could not bring myself to believe that a Republican presidential candidate could have chosen someone so ill-equipped for the job. But I was wrong, and I now accept that. McCain has not been a well man. He is 72 years old and has had cancer four times. His whole demeanour indicates that he might well not live through a whole four year term. Yet despite the intensity of the vetting process, he still chose Sarah Palin, a woman whose charisma temporarily masked her complete unsuitability to be one heartbeat away from the Presidency. And so to Obama. This is what I wrote on 30 January, just before Super Tuesday...

And so we come to Barack Obama. At the risk of being called a 'traitor' by Donal Blaney, I like what I see. He certainly talks the talk, but I still have doubts about his judgement. He's made several errors so far in taking bad policy positions, but he seems to have this Reaganesque ability to shake them off as if he were made of Teflon. Hillary doesn't seem to be able to land a punch. Whenever she starts having a go, he smiles as if he is almost taking pity on her. Maybe he is.

So for me, it's Obama v McCain. My tribal instincts will no doubt win in the end and I'll reluctantly support McCain, but if Obama starts coming out with a more sensible policy platform, you never know.

I have doubts about Obama's Iraq policy, I have doubts about his big government agenda but I have come to believe that he is what America needs if it is to restore its reputation in the world. He radiates optimism. He has the zeitgeist in a way that McCain doesn't even know what the word means. I am not going to pretend I am totally in tune with Obama, because I am not, but on balance I think he would be a better President than McCain, both for America and for the rest of the world.

Last night I emailed my best friend Daniel Forrester, an American who lives in Washington. He's a staunch Republican but I know he shares my doubts about McCain. I told him what I had written in the Telegraph. This is what he replied...

I can see why you would vote for Obama. The Republican party has disintegrated to the point of being meaningless. Bush and Cheney dismantled all that conservatives believe in and in their wake is a confused party with a million followers pulling each other in two million directions. Like the economy of the US in the post credit crisis, it will take years for the Republicans to rebuild and have their words mean something.

I then asked him if he too would vote for Obama. "I cant do it", he said. "My heart says Obama my mind says no. I will stand at the ballot box and write my name in. Obama has one thing that I do like above others. He has the capacity to listen and take in diverse points of view. Our country needs that more now than ever."

I am sure many Conservatives friends of mine will be both surprised and horrified that I could bring myself to support someone who many on the right see as a man of the left. I don't see him that way at all. But my support will be more tacit than active. I'm not going to suddenly turn into an Obama cheerleader. If I like something McCain or Palin say or do, I shall say so.

Anyway, do please go and read my Telegraph column and let me know what you think. I'm putting on my body armour...

UPDATE: Donal Blaney thinks I have lost my marbles.