To paraphrase Winston Churchill's words about the battle of El Alamein and its place in the Second World War, this month of January does not signify the end of the race for the Republican presidential nomination, nor even necessarily the beginning of the end. But it is very much the end of the beginning.
Within three weeks the nature of the campaign will change completely. Retail politics – where candidates go from town to town meeting individual voters in the flesh – may be the stuff of yesterday's Iowa caucuses, next Tuesday's primary in New Hampshire and, to a lesser extent, 21 January's South Carolina primary. But after that, the campaign goes wholesale.
For months, Iowa and New Hampshire, two small and demographically unrepresentative states accounting for less than 1.5 per cent of the US population, have hogged all the attention. But thereafter the focus shifts to big states and big media markets, rich in delegates, where candidates deliver their message to voters not in person, but through costly TV advertising and their ground operations. What counts is the money, and above all the organisation, at their disposal.
Take Rick Santorum, who according to final pre-caucus polls was surging in Iowa, the reward for 200-plus days he has spent in the state, visiting every one of its 99 counties. But the former Pennsylvania senator won't be able to repeat those tactics again.
Belatedly, donors are opening their wallets; Mr Santorum claims he has raised more money in the last six days than in the six previous months. But Mr Santorum must now set up a campaign infrastructure in states where he has barely set foot. Only on Monday did he air his first ads in New Hampshire and South Carolina – and the experience of Mike Huckabee in 2008 underlines the difficulty of his task.
Four years ago, Mr Huckabee mobilised Iowa's social conservatives to defeat Mitt Romney – the very feat Mr Santorum was hoping to emulate last night. But Mr Huckabee would prove no match for the better-known, better-organised and better-financed John McCain, who wrapped up the nomination by early March.
For McCain four years ago, read Romney now. The first big state primary comes in Florida. Even as their man was staging a final weekend blitz in Iowa, the Romney campaign was mailing absentee ballot forms to potential supporters in Florida ahead of the 31 January primary vote. Mr Santorum cannot hope to match that – indeed no other 2012 Republican can.
Of Mr Romney's six rivals, only Ron Paul has something approaching a national organisation, thanks to a devoted following built up in earlier presidential runs. In terms of money, probably only Texas Governor Rick Perry can match Mr Romney.
But in 2012, all is not lost for the outsider. For one thing debates, more numerous than ever this year, will provide a continuing free platform. Both the primary calendar and the delegate allocation system are kinder too. After Florida comes a four-week interval before the next important contests in Arizona and Michigan on 28 February, offering a chance to get a national infrastructure in place. Moreover, delegates in the early primaries will be awarded proportionally, rather than on the winner-take-all basis used previously. This means that no candidate can numerically wrap up the nomination by "Super Tuesday" on 4 March, when 10 states, including Ohio, Georgia and Massachusetts, hold primaries and caucuses.