There was a thread on US politics on Mumsnet a while back. Comparison between the Tories and the US Democrats isn't my area of expertise, but if you do a search the thread may well still be there. I'm not an apologist for the UK right of course - can't stand them.
Did a quick google, and an article from the Telegraph came up. I'm sure you could find a lot more. This is an extract (and have to go to bed now):
There is no proper Left in American politics even Obama is more Right-wing than Cameron
By Walter Ellis US politics Last updated: March 7th, 2012
332 Comments Comment on this article
Note that Dave is on the Left (Photo: PA)
I want you to imagine a twelve-inch ruler, like the ones those of us of a certain age used to pack in our schoolbags. On the far left, just above the 1, picture Trotsky and his band of crazies; on the far right, at 12, Hitler and Genghis Khan.
Where on this scale would you place David Cameron? Id put him at the seven-inch mark, a little to the right of Clement Attlee but definitely to the left of Tony Blair. This measured approach recognises distinctions down to a tenth of an inch, allowing Ed Miliband to sit fractionally to the left of the Prime Minister and just to the right of Nick Clegg.
Now picture a similar ruler used to define United States politics. A very different, and quite frightening, picture emerges.
Where the House of Commons covers a spread between four and nine, with the majority fitting in between five and seven, the US Congress starts at six and runs all the way up to ten, or even ten-and-a-half. Appropriately, most Democrats are at sixes and sevens; Republicans cluster around nine.
Barack Obama, like my fathers hat size, is seven and an eighth, just to the right of Cameron. Mitt Romney, the Republican most likely to face Obama in Novembers presidential race, is a solid eight; Newt Gingrich, the acerbic former House Speaker, now in ill-tempered retreat, is a nine; but Rick Santorum, the arch-Catholic candidate from Pennsylvania, is not only, like Bo Derek, a Perfect Ten, he is a Ten who throws up at the mere mention of the separation of Church and State.