Obama’s choice of a running mate will be the first important decision he makes with the whole country watching, so it will be a momentous act of self-definition. If he chooses her, it will be an act of self-diminishment, especially now that some of her acolytes are aggressively suggesting that some unwritten rule of American politics stipulates that anyone who finishes a strong second in the nomination contest is entitled to second place on the ticket.

Behind the idea that Obama should run in harness with Clinton is this wobbly theory: Because the Republican Party is in such bad odor, if you unify the Democratic Party, that will suffice to win the election, and she is a necessary and sufficient catalyst of unity. But she is neither. She would be a potent unifier of John McCain’s party, thereby setting the stage for exactly what the nation does not need: another angry campaign of mere mobilization rather than persuasion.

A little mutual assured destruction between the Bush administration and Congress could leave the Republican nominee, who will most likely have no affiliation with either, in decent shape.

And what happens when voters realize in November 2008 that, if they choose a Democrat for president, they’ll also get a Democratic Congress and therefore liberal Supreme Court justices? Many Americans will recoil from the prospect of being governed by an unchecked triumvirate of Hillary Clinton, Nancy Pelosi and Harry Reid. So the chances of a Republican winning the presidency in 2008 aren’t bad.

With national polls showing John McCain catching a wave after his pick of Sarah Palin as a running mate, Clinton was asked about the state of the race. He replied: “I predict that Sen. Obama will win and win handily.”

So how does John McCain win Ohio? In the previous post I basically said it was impossible, but as near as I can tell McCain has already settled on a strategy: he’s going to run a very negative campaign in which he hammers on Obama as (a) naive about foreign policy, (b) unqualified to command the military, and (c) ready to surrender to al-Qaeda and squander the sacrifices of thousands of brave American soldiers. His supporters will help out with plenty of talk about terrorist fist jabs and “slips of the tongue” in which they call him Osama on national TV.

I don’t think it’ll work, but it’s pretty obvious that this is the direction things are going. McCain seems likely to make this into a pretty ugly campaign.

And as long as I’m making grand pronouncements that quite possibly might make me look like an idiot in the near future, here’s another one: among the states Bush won in 2004, I think Obama will win Ohio, Iowa, Virginia, Colorado, New Mexico, and maybe even Arkansas. That’s even accounting for the fact that he’ll lose a few points in some of those states for purely racial reasons. This might officially make me the most optimistic Obama supporter in the world, but there you have it.

It was just this toxic stew of inadequate fund-raising and hostility from the base — along with incompetent management — that capsized the McCain campaign last summer. Now the management, at least, is said to be new and improved, but the press is still so distracted by the “divided Democrats” it has yet to uncover how that brilliant McCain team spent weeks choreographing the candidate’s slapstick collision with a green backdrop and self-immolating speech in prime time two weeks ago.

The only figure in the McCain camp who has candidly acknowledged any glitches is his mother, the marvelous 96-year-old Roberta McCain. Back in January she said that she didn’t think her son had any support in the G.O.P. base and that those voters would only take him if “holding their nose.”

The ludicrous idea that votes from Clinton supporters would somehow make up for McCain defectors is merely the latest fairy tale brought to you by those same Washington soothsayers who said Fred Thompson was the man to beat and that young people don’t turn up to vote.

Gallup’s latest Obama-McCain tracking poll shows exactly what you’d expect: now that Obama is firmly the Democratic candidate, he’s making up considerable ground. There will be more ups and downs, especially around the conventions, but I’ll bet that Obama never has much less than a five point lead for the rest of the campaign.

From 1968 through 1988, we had six presidential elections. During that time, Democrats won the Congressional vote by an average of more than 10 points; they controlled the House of Representatives for all of that period, and the Senate for most of it. But the Republican presidential candidate won five of those six contests — four of them (1972, 1980, 1984 and 1988) easily. This year’s election could see a return to this cold-war model — a strong-on-national-security and supporter-of-middle-American-values Republican presidential candidate prevailing, while at the same time voters choose a Democratic Congress. Last week’s developments — in West Virginia, Sacramento and Jerusalem — have increased the odds of such an outcome.