Sen. John McCain is 71 and most likely will be the last Old Guy presidential candidate from you boomers. Goodbye, Great White Father in Washington.

It happens as you age: Other people get younger. The pilots flying you to New York are teenagers. Your banker, your therapist, even your urologist is young.

Still, you go along thinking of the Leader of the Free World as your old civics teacher, genial, omniscient, wielding his pointer, patiently answering dumb questions, and then one day one of your classmates has the pointer in hand and he is not one of the smart ones. It's a big whoosh in your life: Mr. Teacher has left the building and Larry has taken over.

It's a long throw from McCain's 71 to Sen. Barack Obama's 46 and that may be the big invisible issue in the fall: Do we feel better with Papa at the helm or the whiz kid brother? It's a visceral choice you make without thinking too hard about tax policy or judicial appointments. For people like me who think the war in Iraq is a horrible wrong turn, it's an easy choice, but the election won't be decided by people like me — it'll be decided by people who could go either way and who make up their minds at the last minute.

Papa appeals to us because we're sentimental and we assume he's learned a few things. (One could argue that you learn more of the right things in the Illinois legislature than in the Elks Club that is the U.S. Senate, but never mind.) The beauty of the kid brother candidate is the plain hope that we can put a chunk of the past behind us and not keep reliving it over and over. Our 51-49 national impasse. The culture wars. Our mutual misapprehensions. Old debates that we're sick of and that go nowhere. Let's get out of this political boneyard where old hacks sit grinding their gums over the burning questions of 1968. We're done with the Current Occupant, who is dead wrong and proud of it. Time to leave the ranch and head for the 21st century.

I'm the father of a sandy-haired, gap-toothed 10-year-old girl and I realize that whoever we elect in November will be the first president of her memory, just as Ike is mine.

This morning I heard my daughter talking upstairs and realized she was on the phone with her friend Missy. In the past, she asked permission to call. Now she's crossed a line, going outside channels, venturing beyond my protection, such as it is, and that, gentle reader, is the reason for my interest in politics.

Politics is a matter of yelling and shaking your fist at the idiots who want to drive 30 mph down a residential street. Or the ones who would bulldoze great old buildings and put up office sheds. Or the ones who've destroyed public higher education in this country (it ain't public if it costs an arm and a leg to attend).

I want my kid to grow up in a society that values knowledge and hard work and public spirit over owning stuff and looking cool. That's why I live in Minnesota. It isn't for the climate.

March in Minnesota is dreary. Cabin fever sets in, stir-craziness, malaise, depression, whatever you want to call it. I'm a liberal but I don't expect government to solve the March problem, nor am I sure I want it to be solved. Sometimes I think about a spa on a hill outside Albuquerque where a masseur plays your muscles like a mandolin and you sit naked and blissful in steaming water and listen to the buzzing of the bees in the cigarette trees near the soda water fountain, but I'm okay waiting for spring. I accept March, it's a good month to get work done.

I do, however, believe in the big leap by which you skip a mess of complicated trouble and move on into the future. Johnson's Civil Rights Act, Nixon's trip to China, Gerald Ford's pardon of Nixon, the demolition of the Berlin Wall — great moments when we turned the clock forward.

That hope for the leap forward seems deeply felt this year. And that's why people are looking at the skinny guy. They don't want to be replaying old tapes next spring. They just can't bear the thought of going through the past seven years all over again.

Garrison Keillor's "A Prairie Home Companion" airs 6 to 8 p.m. Saturdays on KHPR FM 88.1 and 6 to 8 p.m. Sundays on KIPO FM 89.3 His column appears Wednesday at www.honoluluadvertiser.com/opinion and in Sunday's Focus section.