ELKHORN, Wis.  Still early on a recent weekday morning, the mostly elderly crowd that half-filled a hall in this small town looked like it might be thinking about another cup of coffee. But Representative Paul D. Ryan, the rangy Republican who represents this southeastern Wisconsin district, was in full PowerPoint roll, gesturing and barking out, in staccato tones, why the nation must make major changes to Social Security and Medicare.

“The question is, Could this happen here?” Mr. Ryan said, as an image of a burning street from the recent riots in Greece flashed on a screen behind him.

“Do you want this welfare state, which puts us down this tipping point, advances this culture of dependency, moves us away from the America idea toward more of a Western European social democracy welfare state? Do you want that which invites a debt crisis? Or the alternative party is offering you an opportunity society on top of a safety net where we reclaim these ideals and principles that founded this country. That’s what we owe you. And if we get back in office and we shrink from that challenge, shame on us.”

In this highly charged election season with both houses of Congress at stake, not a lot of politicians are lining up publicly behind Mr. Ryan. He is, nonetheless, suddenly a rising star in some corners. And like many other politicians whose ideas were once considered extreme, only to later be mainstream  like Ronald Reagan  Mr. Ryan is seen as on the leading edge of something.