As the general-election campaign begins, one critical question is whether both parties will be able to unify around their nominees. Will dissidents swallow their grievances and back their standard-bearers in November?

History and logic suggest the answer will be yes. And this year the most powerful reasons for unity can be summed up in two little words – judges and vetoes.

The powers of a president are sometimes hard to quantify. How do you measure the role of the bully pulpit, the ability to set an agenda and mobilize public opinion? And when a president loses credibility – as the current incumbent demonstrates – his influence shrinks with his popularity ratings.

But even the most derided president retains two basic constitutional powers: to make appointments and reject legislation. And that fact will – or should – be enough to convince all but the most disillusioned diehards to get on board.

The process of reconciliation will take time. Wounds suffered during the primary season are still fresh. In many states, about one-third of all Hillary Clinton supporters said they would not vote for Barack Obama, and resentment is particularly raw among female voters who felt their candidate was denigrated and derailed by ingrained sexist attitudes.

They have a point. Voters (and many TV commentators) seemed far more tolerant of words, descriptions, jokes and cartoons ridiculing Clinton’s gender than Obama’s race.