Why Republicans and Tories no longer see eye-to-eye
Once upon a time, and not so long ago in political terms, the Anglo-American world was joined at the hip, and the surgical pin that held the two together was "conservatism".
Margaret Thatcher and Ronald Reagan, and the "isms" attached to their name were so close you could hardly understand why there had ever been all that commotion in 1776.
The recent mid-term election demonstrates that is no longer the case.
A lesson from British history illustrates my point: from the time the welfare state was created, Britain ran a three-level secondary education system. The top level was the grammar school - entry was gained by outstanding performance on a test given at the age of 11. State-funded grammar schools opened the door to elite education for many working-class and lower-middle-class kids. If you've seen Alan Bennett's The History Boys, you know the story.
Throughout the 1960s, Harold Wilson's Labour government brought changes to the education system, the old elite versus equal argument was deployed. Grammar schools were forced to close, or accept pupils regardless of their academic ability.
If you are a conservative by preference you are probably snorting as you read this. That's socialism for you, you are probably thinking, reduce everything to the lowest common denominator.
Undoing what's done
In 1970, the Conservative Party under Edward Heath won the election and took office. The newly appointed education secretary did not reverse the Labour Government's policy and allowed grammar school closures to continue. The name of the education secretary was Margaret Thatcher. Yes, the distaff patron saint of modern conservatism ended up overseeing more grammar school closures than her socialist predecessor even though she, and Mr Heath, had both attended grammars.
The reason I tell you this story is that it shows how Margaret Thatcher - the conservative's Conservative - believed that in order for democracy to work, new governments cannot come into office and simply spend their time undoing what the previous government has done.
Yet in the wake of their victories in the mid-term election, the Republican Party has nailed its colours to repealing the health legislation passed earlier this year.
Ohio Republican John Boehner, who will be the next Speaker of the House of Representatives said after election night: "We have to do everything we can to try to repeal this bill."
Senate Republican Minority Leader Mitch McConnell of Kentucky plans to file a friend-of-the-court brief in Florida supporting states who want to repeal the act.
There is also a contrast with how the Conservatives have behaved on their return to power this year, after 11 years out of office.
Getting the house in order
With their Liberal Democrat coalition partners, they are focused on getting Britain's financial house in order, not undoing the legislation passed during the Blair-Brown years.
Structural deficit reduction - double quick, inside four years - is the goal of Prime Minister David Cameron's government. American conservatives would say deficit reduction is our goal as well. But British Conservatives are putting up taxes, to get the deficit down, as well as making cuts to government spending across all departments except one: the National Health Service.
Republicans want to repeal health legislation, Conservatives know they would not have been returned to office without Mr Cameron's eloquent commitment to the NHS.
This is only one of many examples of how "conservatism" no longer means the same thing among people who call themselves "conservative" on either side of the Atlantic.
Cameron and Co are cutting defence spending. Yes, cutting defence, by 8%. The coalition government has not challenged the view that this means Britain will no longer be able to march to war with America the next time the US wants to fight in the Middle East.
Welfare is being cut - dramatically - but it is not being eliminated. It is being reformed.
To the chagrin of some of its old guard, Britain's Conservative Party would not waste a moment campaigning against the idea of man-made climate change - indeed it campaigned last spring on how to grow the economy by funding solutions to the problem. Compare that to the Tea Party/Republican Party view on climate change.
To modern British Conservatives fighting culture wars seems a waste of political time. Gay lifestyles? That's a non-issue, there are a number of out gay men in the British cabinet. Science using stem cells derived from human foetuses? Prime Minister David Cameron's son suffered horribly in his brief life from a variety of nervous system disorders. Mr Cameron would not stand in the way of any research that might help future sufferers of Ivan's myriad problems.
Perhaps the most profound difference today between British and American Conservatives is in the response to terrorism. British Conservatives are libertarian in striking the balance between security and personal liberty when it comes to living in a world where al-Qaeda operates.
They have stopped funding for national ID cards - an expensive programme of the Labour government - and shut down many of Britain's CCTV cameras. Critically, they are considering repealing Britain's 28-day detention law for terror suspects. This law allows police to hold those suspected of plotting terrorism for 28 days without charging them. No other Western democracy gives the police this kind of power.
Republicans have been against shutting down Guantanamo and trying those detained there in civilian courts. I cannot see them renouncing a law allowing police to detain a suspect for a month without charge.
Unlike Margaret Thatcher, British Conservatives no longer echo Ronald Reagan's view that government is the problem not the solution.
But the important point is this: Mrs Thatcher and Mr Reagan shared a governing philosophy: ideology and pragmatism. Ideology was great for speech-making and letting people know what you thought, pragmatism was necessary for governing. As American and British Conservatives drift apart, like Gondwana and Pangaea, it seems that American Republicans have let go of their pragmatic inheritance.
Without pragmatic respect for what previous governments have done, can they really be considered "conservative" in the true meaning of the term?