Interesting, but I have to take exception to the author's statements:
In America, neo-conservatives call themselves neo-liberals when it comes to economic theory. They advocate liberal interventionism in foreign policy.
I have never heard a neo-con in the USA call themselves anything but a conservative. Regardless of what they think 'conservative' means, 'liberal' is a dirty word to them and they'd sooner call themselves child molesters.
I agree with this statement:
British Prime Minister David Cameron is, by the current American usage of the word, a liberal.
He accepts the basic science surrounding climate change theories and is an advocate of gay rights. He even calls himself a progressive.
The word liberal has been so debased in America by right-wing demagogues that liberals have for at least two decades preferred to call themselves progressives.
I may be able to assist with his last statement, though:
It really is confusing - although perhaps the real transatlantic confusion is not over the meaning of the word liberal but over the meaning of the word conservative.
The use of the term 'conservative' has also been hijacked in the USA. In my day, and for me still, the word means what people like Barry Goldwater and to some extent George Will believed; beliefs which now encompass both the libertarian and conservative spectrum. Limited government, a weak central government and strong state governments, a strong military, free trade, protecting American interests overseas through diplomatic and other means as required, and a strong core belief that the Constitution is not meant to be 'interpreted' according to the current zeitgeist, but is to be interpreted strictly based upon the intent of the Founders.
Now, we find that the remnants of the Religious Right, which utterly wrecked the Republican Party, has also co-opted the term 'neo-con' and adopted it as their own moniker. Moving away from their religious conservatism, they now appear to have embraced a moving target of populism and populist anger and ennui against the outrage-du-jour. Their outlook is less conservative and more 'what makes me maddest today'?
Liberals in the USA, properly identified as 'progressives' in the sense apparently meant by the term in the UK, have retreated into either outright socialist bleatings about the need for the State to intercede in every aspect of human life, or have simply gone silent on the issues, only opposing and mocking the new 'conservative' agenda without presenting one of their own.
It's a mess. I continue to call myself a 'conservative'. I can't call myself a Republican anymore. I would never consider myself either a Democrat or a Liberal (or even a Libertarian), although I have ameliorated some of the stances I used to have over government regulation; I am now much more amenable to some regulation than I used to be; so that's a bit of a shift to the left for me personally.
And although I tend to dislike both Republican and Democratic politicians with equal intensity, if given no other choices, I'll almost always pull the lever for the Republican. Democrats are in too much of a hurry to spend my money, and I'll never vote to have my paychecks made smaller.