Most people's views of the world are shaped by the times in which they came of age. That's why we speak of a baby boom generation or a Generation X. But some people miss out on the formative experiences of most of their peers. That's the case, I think, with the Republicans' certain nominee and the front-runner for the Democratic nomination. John McCain missed the 1960s. Barack Obama missed the 1980s.

That's obvious in McCain's case. He was a prisoner of war in North Vietnam between 1967 and 1973 -- the years of the march on the Pentagon, urban riots, campus rebellions and Woodstock.

He made the point himself last October when he attacked Hillary Clinton's proposal to earmark $1 million for a Woodstock museum. "I wasn't there. I'm sure it was a cultural and pharmaceutical event. I was tied up at the time."

And it's part of a larger point. Much of our politics over the past two decades has seemed to be a cultural civil war between the two halves of the baby boom generation, between the cultural liberalism of Bill Clinton and the cultural conservatism of George W. Bush. The resulting polarization has embittered our politics, as the odd couple of Cal Thomas and Bob Beckel argue in their new book, "Common Ground: How to Stop the Partisan War That Is Destroying America."

To most voters, McCain seems to stand above or at least aside from that culture war. His lack of fervor about issues like abortion may bother some cultural conservatives, but it is comforting to those with more ambivalent views. If elected, McCain would be the only president from the "silent generation," born between the World War II veterans who served as president from 1961 to 1993 and the two boomers who have served since then. His age and generational identity may turn out to be a political asset.

Obama, born at the tail end of the baby boom generation in 1961, didn't miss the '80s in the same sense that McCain missed the '60s. But in a decade in which Americans decided that government didn't work very well and that markets did, Obama chose to make his way outside the suddenly booming private sector.

As a community organizer in Chicago and a student at Harvard Law School, he inhabited a part of the nation where it did not seem like, in the words of the 1984 Reagan ad, "Morning in America." From then until now, he has continued to believe in big government programs -- "investing in the health, welfare, and education of black and brown and white children," as he put it in his speech on race last month. And to insist on addressing the grievances he says are behind his pastor Jeremiah Wright's controversial statements.

To many voters, it may seem that Obama is proposing the kind of overgenerous welfare programs that were finally rejected in the backwash of the '80s, and in that same speech he concedes that such programs may have had bad effects. But that may be counterbalanced by Obama's appeal to black voters and to the millennial generation (born after 1980) who, like him, missed the '80s.

Clinton, still in contention though behind in delegates, experienced both the '60s and the '80s in full measure. Like her husband and his successor, she polarizes the electorate along cultural lines, and the cultural civil war of the baby boom generation seems likely to continue in a second Clinton administration. The moderate stands Bill Clinton took in the 1990s -- supporting NAFTA, for example, or signing the 1996 welfare bill -- are liabilities rather than assets for her, at least in the primaries.

No one candidate can embody the experiences of the whole electorate, of course, and many presidents have lived highly atypical lives. Dwight D. Eisenhower was a career military man, John F. Kennedy the son of a multimillionaire, Ronald Reagan a movie actor. But it's unusual to have two front-runners who have missed out on the formative experiences of so many Americans -- though perhaps not surprising in a political year that has already given us more surprises than most.