This is the closing of the first chapter of America’s health-care saga,” Rep. Paul Ryan says from his office, which is adorned with reminders of contests of the non-political kind: hunting mementos and a Green Bay Packers helmet. “We are witnessing the beginning of a whole new kind of health-care politics, the likes of which we have never seen before.”

Ryan, a 40-year-old Wisconsin Republican, says Republicans have a fight on their hands, and he is ready for combat. As Democrats scrambled this past week for votes, he’s been listening to Metallica on his iPod and strategizing about how best to counteract Obamacare. Sunday night’s passage, he says, “was a rude awakening and a big wake-up call,” but also a call to action for Americans — and, especially, for the GOP.