Leading article: In search of a graceful exit

Within a week it will be over – or so at least the Democratic high command is praying. On Tuesday, Montana and South Dakota hold the party's final two contests of this protracted and gripping US presidential election primary season. The winner in both of them is likely to be Barack Obama, already all but certain to be the party's nominee to face John McCain in November. The real question is not whether Hillary Clinton concedes defeat – but how.

True, a couple of hurdles remain. Today the party's rules committee meets to settle the vexed question of how the delegations from Florida and Michigan will be seated at the Denver convention. The most likely outcome is a compromise that hands a small advantage to Ms Clinton, but not enough to overturn Mr Obama's commanding lead in the delegate count. Tomorrow Puerto Rico holds its primary, which the former first lady is expected to win convincingly. Here again, however, the result will not change the larger delegate picture – although combined with the revised solutions for Florida and Michigan it might enable her to claim that she has won a greater share of the popular vote than her rival.

Statistically and, even more important, psychologically, Mr Obama has all but sealed the nomination. On the campaign trail, he has already switched his fire to his Republican opponent. Ms Clinton soldiers on, but the sporadic fulminations of her husband notwithstanding, she seems tacitly to acknowledge that the game is up.

Or so at least her party is hoping. There is another possibility that every Democrat dreads, that she will carry the battle all the way to Denver, perhaps by way of the courts. In as litigious a country as the US this cannot be ruled out, and if it happened it would be disastrous. Instead of closing ranks, the party would place its divisions on glaring display, jeopardising its chances in the Democrats' most obviously winnable election since 1976.

The sheer direness of this prospect is the strongest reason for believing it will not happen, that Ms Clinton will be prevailed upon to make a graceful exit. This was always going to be an especially intriguing election. Sadly for her, the historic question it will answer is not whether America is ready to elect its first female president, but whether it is ready to send an African-American to the Oval Office.