David Usborne: The hobbits have had a gun to Boehner's head from the start

The Tea Party and the 80-odd freshman Republicans it helped send to Congress last November had a good reason to celebrate last night with something with bubbles in it rather than milk and sugar. Yet such is their zeal for constraining government it was barely able to savour victory even when handed it by "cave-in" Barack Obama.

Congresswoman Michele Bachmann, whose harnessing of the Tea Party enthusiasm has made her a contender for the Republican 2012 nomination, cancelled her campaign appointments in Iowa to rush back to Washington in time to vote "no" on the debt-ceiling deal when it comes to a vote in the House. No one could say any more that the Tea Party spasm that began after Mr Obama's election and his Obamacare crusade is not to be taken seriously.

Senator John McCain prefers still to call them "hobbits", but if they are short, they are certainly strong. No wonder Senator Rand Paul, the most visible Tea Party newcomer in the Senate, shot back that he'd rather be a hobbit than a "troll".

The Tea Party rump has been at the centre of the action over this issue from start to finish.

Even last night as the House prepared to vote on the compromise to avert default, eyes were on Bachmann and her crew. Would they find common cause with progressive liberals in the House (and defence-hawk Republicans) to defeat it and plunge the country and the world right back into the crisis they had just escaped from?

The Tea Party might have less power if the Republican gains last November had been even greater. But with only a small majority, House Speaker John Boehner has been forced to heed their demands.

His first attempt at a deficit-cutting plan last Thursday had to be pulled because of Tea Party resistance. The hobbits have had a gun to his head from the start and, therefore, to the head of President Obama as well.

"Someone has to say 'no'. I will," Ms Bachmann rumbled. "The 'deal' ... spends too much and doesn't cut enough," she said. "Mr President, I'm not sure what voice you're listening to, but I can assure you that the voice of the American people wasn't the voice that compelled Washington to act."