Barack Obama's decisive victory over Hillary Clinton in South Carolina's Democratic primary projects him powerfully into the national contest on Super Tuesday, February 5th - and beyond it.
As the favourite candidate, he could not have lost this battle, but to win it so handsomely has real national significance. Successful weathering of the ill-tempered attacks on his record from the Clinton camp last week has toughened him up and should lead his opponents to reappraise their electoral tactics as the competition intensifies.
Exit polls indicate the extent of Mr Obama's victory (although it should be remembered that South Carolina is normally a majority Republican state). Turnout, at 530,000 voters, was substantially increased, especially among blacks, who supported Mr Obama by an 80 per cent margin. That included a solid majority of black women - despite the Clintons' efforts to win their support. Young voters, both black and white, also preferred him, as did the better educated. The three-quarters of white voters who did not vote for Mr Obama split 50/50 between Mrs Clinton and John Edwards, who came third with 18 per cent of the vote, against 27 per cent for Mrs Clinton and 55 per cent for Mr Obama. This was a disappointing result in his home state; but most white males voted for Mr Edwards and he is likely to remain in the race.
The full fury of the Clinton machine was unleashed against Mr Obama's allegedly inconsistent foreign policy record - notably on Iraq; on his supposed policy incoherence, vacillation; and on his praise for Ronald Reagan's transformative cross-party appeal. Above all, there was explicit and implicit reference by Bill Clinton to his wife's more universal appeal, in contrast to Mr Obama's limited support among white voters.
This invocation of the race issue attracted much criticism, but it did provoke Mr Obama to retaliate in kind, thereby tarnishing his carefully cultivated appeal for a new kind of politics. However the uncanny resemblances between Mr Obama's persona and message and those of Bill Clinton in 1992 have attracted much comment. It is Mr Obama's misfortune to face a twin-headed candidate. This result shows he is well able for the challenge.
It would still be wrong to extrapolate over-much from South Carolina to the Democratic contests on Super Tuesday, when 22 states vote. February 5th will be a genuinely national contest. It will test the demographic appeal of the three main Democratic candidates. That matters between Mr Obama and Mrs Clinton, because otherwise their policy profiles are rather similar, despite last week's hostile exchanges, whereas Mr Edwards's more left-wing populism is more distinctive.
The Clintons' message about Mr Obama's restrictive appeal was aimed just as much at the national audience as South Carolina. It would be a cruel irony if Mrs Clinton thereby won the nomination but failed to win the presidency because of the bad feelings stirred up last week.