The Gore Breakup: Why, After All These Years?

Et tu, Al and Tipper? When statisticians try to figure out the divorce rate, which is a complicated formula at the best of times, they stop counting after a marriage passes the 40-year mark. If a union lasts that long, it's considered to be successful. Moreover, says Penn State sociologist Paul Amato, "so few couples divorce after 40 years, it's statistically not that significant."

This is one of the facts that makes the out-of-nowhere announcement about Al and Tipper Gore's "mutually supportive" separation such a head scratcher. What on earth happened? After four decades, having reared four children, nursed their son through a terrifying car accident, endured four presidential campaigns, invented the Internet, tried to hold back the tide of vulgarity in popular music and made everyone aware of global warming — having slogged through, in other words, all the hard stuff — now the two of them decide they just can't do this anymore?

The obvious conclusion, that one of the Gores took a detour onto the Appalachian Trail, has been denied by people who know them. So what could it be? "What often happens is that the fun goes out of the marriage," says David Arp, who with his wife Claudia is the author of The Second Half of Marriage. "And when that goes, the old hurts resurface." For the Gores, who have lived such full lives, many discussions and issues must have been delayed, and they may have let the baggage get too heavy. "Usually, one person is feeling more pain, and it's very hard after all that time to wipe the slate clean," adds Arp.

Another big strain on a long-term marriage, experts say, is life change. Did Vice President and Nobel laureate Al have trouble hiking down from the pinnacle of achievement? With an empty nest, did the two have less to talk about? "Couples have to be willing to go from a child-focused marriage to a partner-focused one," says Claudia Arp. "But often they fill up the vacuum left by the kids with activities or a career."

And then there's the added burden put on any relationship by being in the public eye. The Gores have never been shy about showy displays of affection. But when a couple is constantly on display, it can be hard to build trust and comfort and to relax in each other's company. There's a feeling that somewhere, someone is always keeping score.

As anybody with long-married parents knows, a union of more than 35 or so years is not always pretty to behold. Some couples can't get past the petty things: how their spouse puts the dishwasher on before it's full or insists on wearing ratty old shirts in public. Others are worn down by their life partner's temperament, the negativity, the lack of curiosity, the insistence on always taking credit for everything. Or they nurse long-held grievances that color every interaction. But still many stay together: out of habit, out of duty or out of a deep companionate love, despite everything, for their spouse. Or perhaps simply out of a fear of being alone.

It may be that now that the Gores have no big projects on their plate, no shared obstacle to overcome, no common enemy, they finally had time to take a hard look at each other, and decided they did not enjoy the view. Or it may be that they had been so busy that they grew apart and the chasm was too wide to bridge. Or that after all these years of pretending, they can finally admit they never liked each other. Heck, one of them — my money is on Tipper — could even be a gun for hire like in that new Ashton Kutcher movie. Each marriage is always a mini-mystery. What really happened to the Gores will no doubt come out over the coming days and months (Mark Halperin, your country needs you). But in the meantime, let's all stop for a moment and consider the improbability of this outcome: of all the high-profile political marriages of the past decade, it's the Clintons who are still together.