IN HIS Dallas victory speech on Tuesday night Mr John McCain attacked his Democratic opponents as liberals who lack the experience and wisdom needed to tackle economic troubles at home and waging a war abroad.
Now that he has decisively won the Republican nomination he can relentlessly exploit the potentially prolonged divisions among the Democrats between now and their August convention. The issue of who can best defeat him becomes the critical question facing the Democratic Party. They cannot take victory for granted, even if it is their election to lose.
Despite her convincing and revitalising primary victories in Texas, Ohio and Rhode Island, Hillary Clinton still lags behind Barack Obama in the number of convention delegates committed to her. There is little or no prospect she can catch up with him, even if she wins most of the remaining contests. The issue would then be down to the super-delegates who can decide their preferences individually. Alternatively, an agreement could be reached soon on who has the best chance of defeating Mr McCain.
Mrs Clinton's hint yesterday that a joint ticket makes sense is the opening bid in that negotiation. Obviously she expects to be the presidential candidate. And by demonstrating so clearly her ability to fight back she has strengthened her hand in any such talks. But there is no killer evidence in the demographic profile of these results to facilitate either candidate. Mrs Clinton scored well with Latinos, women and white working class men, Mr Obama among younger voters, better educated ones and blacks. Their fundamental policy differences are relatively small, making competing assessments of their leadership qualities and personalities all the more important.
Given that one third of voters are independent of both major parties, who they support can determine results. On this occasion they swung disproportionately to Mr Obama; and he has shown he can attract more such voters among the white working class, an important consideration for next November's contest. That bears out another of his strengths - that the longer voters are exposed to his campaigning the more they have tended to warm to him.
There is as yet no knowing how this dramatic clash of wills is likely to pan out. It has mobilised a new generation of voters, immensely vitalised the Democrats and attracted extraordinary international attention. But Mr McCain's stature can only grow from now on.