Have you noticed the new political fashion? Marxism is back - Groucho, not Karl. "Those are my principles," goes the quote, "and if you don't like them... well, I have others."
As with so many of the best quotations, no one seems sure that he actually said it, but for my purposes, it doesn't matter. The changing of minds is the order of the day, and it's happening on both sides of the House of Commons.
Is the UK government bidding for a lucrative "training needs analysis" contract with the prison service of Saudi Arabia? (If anyone knows what that is exactly, and why the Saudis might be prepared to pay nearly £6million for it, please get in touch.) Yes, last Monday it was; but, oops, no, on Tuesday it wasn't.
Is George Osborne a fan of fiscal charters or fiscal responsibility bills? In 2010, when he was shadow chancellor, No, he wasn't. Quote: "Fiscal responsiblity acts are instruments of the fiscally irresponsible to con the public." On Wednesday, he proposed just such a measure.
As for the man who is now shadow chancellor, John McDonnell, do I even need to remind you? Three weeks ago, it was: "We accept we are going to have to live within our means ... we will support the charter."
On Wednesday night, it was, oops, No, we won't. "Embarrassing? Yes, of course it is, but a bit of humility amongst politicians never goes amiss."
Then came the education secretary, Nicky Morgan. A year ago, it was: "There aren't going to be any more grammar schools under me ... I am resistant to selective education." And then last week, for a grammar school in Kent, it was, oh well, if you insist.
And finally, at the end of a week of dizzying policy about-turns, the prime minister decided that, contrary to his previous plan, he will now provide the UK's EU partners with a written shopping list of reform demands ahead of his much-anticipated referendum.
It is 35 years since Margaret Thatcher had the party faithful cheering delightedly at the Tory party conference in Brighton: "You turn if you want to - the lady's not for turning." She would not be much impressed by the - what's the polite term: flexibility? - of today's politicians. Groucho Marx, on the other hand, would thoroughly approve.
I'm with John Maynard Keynes on this kind of thing: "When the facts change, I change my mind. What do you do?" (Again, the quote may be apocryphal, but again, it doesn't really matter.) But I do have a problem with the current penchant for political costume-changing, because in all the cases cited above, it's not the facts that have changed but the political weather.
Politicians change their minds when they are persuaded that it is to their advantage to do so. Perfectly understandable, perhaps, but let's not pretend. Why don't more ministers have the honesty to admit, as did the then local government minister 10 years ago when he announced that the government was postponing council tax revaluations, that he had performed a "vaulting, 180 degrees, full U-turn"? (His name was David Miliband, by the way. Whatever happened to him?)
If you like this new political nimbleness - and I have to admit that it does make life a lot more interesting - you can thank Jeremy Corbyn. He's a great believer in mind-changing: on membership of the EU, renewal of Trident, membership of NATO, and, of course, the Osborne fiscal charter elephant trap.
He also deserves credit - shared credit, to be fair, with Michael Gove - for forcing the Prime Minister to drop the UK bid for that Saudi prisons contract. But although I'm pleased they dropped the bid, I have a question for them.
If it's wrong to bid for such contracts in Saudi Arabia, on the grounds that it is a country with a truly abysmal record on human rights, why is the government about to roll out the reddest and plushest of carpets for President Xi Jinping of China, who will be welcomed on a State visit with all the pomp and frippery that we're capable of? He will address parliament, be guest of honour at a State banquet at Buckingham Palace and ride in the royal carriage - and the general message from his fawning hosts will be: "Mr President, if you see anything you like the look of, it's all for sale."
When George Osborne was in China last month, State media praised him as "the first Western official in recent years who focused on business potential rather than raising a magnifying glass to the 'human rights issue'." Somehow, that doesn't make me proud.
Although the number of executions carried out in China remains a State secret, according to Amnesty International it is estimated that there were more people executed in China last year than in the rest of the world put together. Yes, more than in Saudi Arabia, plus Iran, plus North Korea, plus the US and the rest of them.
Perhaps the Daily Telegraph analyst Con Coughlin was right when he wrote: "In the pragmatic world of realpolitik, strategic interests and human rights rarely make for a comfortable mix." But we have certainly come a long, long way since the newly appointed foreign secretary Robin Cook proclaimed after Labour's election victory in May 1997: "Our foreign policy must have an ethical dimension."
Remember those words as you watch President Xi being fêted in London.