Obama-Clinton. Don't rule it out.

I'm aware that the Democratic "dream team" scenario is widely scorned by the practitioners of conventional wisdom. But now that Barack Obama has attained the status of near-presumptive nominee, I wouldn't be shocked to hear a growing clamor for a shotgun marriage, forged for the good of the party. Nor would it be outlandish to imagine that the warring candidates might agree to meet at the altar. Love has nothing to do with it. Pragmatics may well require it.

As political bedfellows, he and Hillary conjoin perfectly. He has the youngsters, she has the seniors. He has the upscales, she has the downscales. He has the white collars, she has the blue. He has the urban, she has the rural. He has the eggheads, she has the salt of the earth. He has the blacks she lost early on, and she has the white women he never got. He could expand the Democratic base while she nails down the Rust Belt. And, stylistically, he is the poetry, and she is the prose.

We've all heard the arguments about why such a union could never happen. A lot of blood has been spilled, and the stain will remain. He has basically called her a devious Washington hack; she has basically called him a naïf who cannot be trusted to command. The staffs hate each other, and the spouses are ticked off, too. Michelle Obama, speaking about Hillary's irrepressible husband, said a couple of months ago, apparently in jest, "I want to rip his eyes out!"

If Obama and Clinton join forces - and neither candidate has ruled out the idea - the press would resurrect the insults and ask how they could suddenly profess mutual devotion after having just spent the year savaging each other. Moreover, Obama would get some heat from his own fans. His candidacy has been grounded in the proposition that it's time to change politics, turn the page, start afresh; if he picked Clinton as his running mate, he'd risk looking like a typical pol who swaps inspiration for calculation when the chips are down.

All good points. The problem is that the same kinds of arguments were made in 1960, when few imagined that John F. Kennedy would choose his vanquished rival, Lyndon B. Johnson; and again in 1980, when conventional wisdom decreed that Ronald Reagan would never pick the guy he beat in the primaries, George H.W. Bush.

Some of the particulars might sound familiar. LBJ resented his more charismatic rival. He thought it was his turn to be the candidate; he felt that Kennedy had cut into line. He assailed "Sonny Boy" as a Senate lightweight with scant experience who "doesn't like the grunt work." Johnson said that America needed a president with "a touch of gray in his hair." He said that Kennedy wasn't tough enough, dismissing him as "a little scrawny fellow with rickets."

And the Kennedys didn't like him, either. Brother Bobby fervently opposed a dream ticket (Catholic and Protestant, Massachusetts and Texas). Jackie privately referred to LBJ as "Colonel Cornpone." The family was furious when Johnson surrogates spread (true) stories about JFK's fragile health, even after it was clear Kennedy had the nomination sewn up. Here's what Bobby said: "Evidently, there are those within the Democratic party who would prefer that if they cannot win the nomination themselves, they want the Democrat who does win to lose in November."

Nobody imagined the Kennedys would willingly bond with a sore loser who seemed determined to imperil JFK in a close election year. Nobody imagined Johnson would agree to subsume his legendary ego by taking the second slot. And yet it all happened. Many of Jack Kennedy's northern devotees went ballistic, claiming he had betrayed the ideals of the nascent New Frontier, but he was swayed by the pragmatics. Johnson was deemed necessary, to help carry the Southern states.

Twenty years later, a similar dynamic occurred. Reagan and Bush were not simpatico. As Reagan adviser Lyn Nofziger later recalled about his boss, "He thought Bush was a wimp." Reagan and his people stewed over the bad blood spilled during the primary season, particularly Bush's skewering of the Reagan agenda as "voodoo economics."

While Reagan was weighing his choice for running mate that summer, he told a friend (according to a Bush biographer) that "I have strong reservations about George Bush. I'm concerned about turning the country over to him." And Bush, for his part, wasn't wild about the Reagan team, either; an establishment Yankee from Yale, he viewed the inner circle as a bunch of nouveau-riche ideologues.

But Reagan ultimately decided (after Gerald Ford said no) that Bush would help build bridges to the party's Eastern Establishment wing. So he phoned Bush and said: "George, it seems to me that the fellow who came the closest and got the next most votes for president ought to be the logical choice for vice president."

That argument apparently resonates among most Democrats today. The latest CBS News/New York Times poll reports that 59 percent want Obama to tap Clinton for the second slot; while only 53 percent of current Obama supporters like the idea, 66 percent of Clinton supporters do, which suggests that a shared ticket would indeed help heal the party.

And Clinton herself could say yes, for reasons of calculation. She'd look like a uniter who puts the party first, thus engendering good will. And if Obama loses in November, she can always say, "I told you so" and prepare to take on John McCain in 2012.

In the end, of course, the idea could prove to be sheer fantasy. It's hard to figure exactly how Obama would handle the possibility of having two vice presidents - Hillary, and the Second Spouse, who happens to be a former president (although it was LBJ who infamously said that it's preferable to have a foe inside the tent urinating out, rather than outside the tent urinating in). And it's important to acknowledge that the shotgun marriages of 1960 and 1980 involved white men; perhaps, this year, a union of black man and white woman would be too transformational for the average swing voter.

But if Obama truly intends to write a new chapter in our history, he may well need Hillary's help to make it happen. They are interlocking pieces on the puzzle, each complementing the other. There are worse reasons to get married.