If politics is theater, then Joseph Biden is Brian Dennehy. The Delaware Democrat plays to the cheap seats like no one else in the 2008 presidential campaign, bellowing his opinions as though he’d been reliably told that the loudest candidate wins. Senator Biden’s stage style is a classic case of overcompensation, from those cheesy hair plugs to his wild-eyed commitment to a no-fly zone in Sudan, and it’s great fun to watch. So are all the candidates, Democrat and Republican; we’re hugely lucky that the cable networks have committed to debates so early and so often in this historic political battle. It’s fun, informative and, best of all, improvisational — a Second City troupe with all the players in black suits.

Sunday night’s CNN Democratic debate in New Hampshire made for riveting television, and not just for those of us who always bliss out when Wolf Blitzer’s in the house. Tonight’s Republican version promises to be just as goofy and entertaining, as cable’s eminence grise forces the gaggle of Reagan pretenders to answer hypotheticals and hardballs in equal measure. (The candidates hate it, but what’s wackier than a group of learned politicians being asked to raise their hands?) It’s the way primary campaigns should have always been run: for the American public as a whole, and not just for the local electorates in states such as Iowa and New Hampshire, and not just within days or weeks of the vote. Now that the cable networks have found a formula that works — throwing all the candidates onto a stage together early and often, and letting them have at each other with only a modicum of control — we can look forward to numerous evenings of political theater with more relevance than “Frost/Nixon,” and with closer proximity to the refrigerator.

If you think it’s too early to care, you’re missing some great performances, and may never get the chance to appreciate the zany antics of the fringe political performers who give these evenings their edge. They’ll be gone by next year at this time. I’m referring, of course, to Democrats Dennis Kucinich (only marginally less loony in real life than Amy Poehler’s priceless “Saturday Night Live” impression of him) and Mike Gravel, whose ill-considered, scattershot attacks on his competition make everyone nervous and giggly. It’s fun to have these loopy lefties shape the conversation around their positions. Their pokes over Iraq and immigration even get a slight rise out of Hillary Clinton, whose Botox injections have otherwise rendered her expression disconcertingly blank. (I miss her late-1990s scowl.) Bill Richardson managed to maneuver himself into the frame fairly often, too, even though he devoted most of his energy to reminding us of his lengthy résumé. Someone needs to tell him the presidency isn’t a job you apply for — it’s a position you win.

Meanwhile, John Edwards has clearly been practicing in front of the mirror, and it’s working. The Sunday debate unveiled the former Kerry running mate’s newfound combative streak, and it roiled the room like no other candidate. He knew just when to parry, when to thrust, and when to kiss and make up. It threw the overly genteel Barack Obama a little; Mr. Edwards managed to maneuver himself into the spotlight and push the junior senator from Illinois into the unenviable position of showing gratitude instead of bite. It’s time for Senator Obama to drop lines like “I appreciate John’s compliment” from his repertoire of one-liners, and remember that the words “polite” and “politics” don’t stem from the same root. The best retort he could offer — “I opposed this war from the start!” — had the hollow ring of someone looking for a gold star from the teacher. Even the plainspoken Christopher Dodd was left with little to speak plainly about in the wake of the Edwards jugular juggernaut.

As usual, we have the Wolfster to thank for bringing urgency and drama to the table. And the CNN structure worked perfectly — rejecting the equal time, let’sbe-fair doctrine of MSNBC’s earlier, far deadlier debates — because it acknowledged the imperfect realities of politics, and the demands of prime-time television for star power. By grouping the front-runners together in the middle of the stage, the cameras captured the byplay among the top three candidates — Messrs. Edwards and Obama, and Ms. Clinton — and left the supporting players where they belonged. And by bifurcating the debate into a half-standing, halfseated format, it gave viewers the chance to check out the postures of these potential presidents, not to mention their sheer socks and shiny shoes.