For once, the dour and ultra-cautious Kansas senator could not contain himself. Two hours before the polls had even closed in California, he went before a victory rally a continent away in Washington DC to proclaim what for everyone else has been plain as a pikestaff for a fortnight, that he will be Mr Clinton's challenger in November.
No matter that polls put him far behind the President or that Mr Perot gives stronger signals by the day that he intends to make a second run for the White House. Within the Republican party at least, Mr Dole is the unquestioned master, and the results on Tuesday proved it.
With his 23rd, 24th and 25th straight primary wins, he trounced Mr Buchanan, his sole remaining rival, by a massive 66 per cent to 18 per cent in California, by 52 per cent to 15 per cent in Nevada and 63 per cent to 21 per cent in Washington state, guaranteeing himself some 1,200 delegates at the San Diego convention - far more than the majority required of 996.
"The primaries have clarified the issues," Mr Dole told his supporters. "They've made the party stronger . . . and have opened the way for a winning Republican coalition in November." But putting that coalition together will anything but easy.
Grudgingly, Mr Buchanan has conceded defeat, and today will meet his advisers to plot future strategy.
But although the fiery former commentator now seems unlikely to leave the party and run as an independent this autumn, he intends to take his harshly populist and right-wing message all the way to San Diego, making it harder for Mr Dole to move back to the political centre where he is more comfortable - and where elections are won and lost.
Nor does Mr Dole appear any more successful in his pleas to Mr Perot to stay out of the race.
Moving to exploit the news lull in the campaign as he did in 1992, the Texan businessman this week began a speaking tour around the country to press his new Reform Party, and dropping hints at every stop that, should supporters so decide, he will be only too delighted to be their candidate.
In fact, Mr Perot notwithstanding, the outlook for Mr Dole is less bleak than suggested by the current polls putting Mr Clinton 10 or 15 points ahead. For one thing, that gap will narrow now that he has clinched the nomination. Second, the electoral college arithmetic favours the Republicans.
Barring a powerful independent challenge, several Southern and Rocky Mountain states which voted Democrat in 1992 are unlikely to do so again, meaning that the election's real battleground will be the big Mid-Western states of Ohio, Illinois, and Michigan. And even the independent challenge might not spell disaster.
Although conventional wisdom suggests Mr Perot would take votes overwhelmingly from the Republicans, detailed polling shows his supporters are less well educated and more blue collar than in 1992, and that a 1996 Perot run would hurt Mr Clinton and Mr Dole in equal measure.
And in California, a helpful complication beckons for the Republicans in the person of Ralph Nader, the 63-year-old consumer advocate and Green Party candidate this November, who will take votes predominantly from the Democrats.