There is no real comparison, but all the internal party leadership races in this country have been polite tea parties compared with the mud-slinging in the Democratic race. In Britain it is understood that divided parties don't win elections, which is why we have had no real fun with internal elections since Tony Benn vs Denis Healy in the 1970s.
Not so in the US. Things turned nasty in the run-up to the New Hampshire primary as the Clintons seemed to play the race card. Hillary Clinton and Barack Obama may have drawn back a little since then, but in the run-up to Super Tuesday the closer the pair got in the polls the more they clashed. In the last televised debate, they were reasonably civil, but the gloves were off again as the poll approached.
So, does all this matter? Conventional wisdom in the US is that it doesn't - and once the real race for the presidency starts, what happened in the primaries is irrelevant. This, though, is no ordinary battle. No-one can recall when last a race was so tight. Who knows, the fight may go all the way to the Democratic convention in Denver in August. If that happens, the Republicans will surely benefit.
As the Republican governor of Texas said: 'The sooner we can wrap this up and start kissing each other, the easier it is going to be to win in November.'
The bad news for the Democrats is that the Republicans are having a much better run in the primaries than anyone expected.
The emergence of John McCain as a very credible candidate has come as a complete surprise - even more so now that he has the high-profile support of Rudy Giuliani and Arnold Schwarzenegger. This places him much nearer the centre ground where, as in all elections, the battle will be won.
There is talk about right-wingers in the Republican Party being upset about McCain. They seem to hate him more than Clinton, accusing the Republican senator of lurching to the left by opposing tax cuts and acknowledging that something has to be done about climate change.
There is no doubt, though, that the McCain camp will want Obama to win the Democratic nomination on the basis that he is seen as further left on the political spectrum than Clinton. Ironically, both McCain and Clinton will be pleased about his support from veteran left-winger Teddy Kennedy.
For the first time since the war in Iraq, the spectre of a Republican replacing George Bush is looking like a real possibility.