But Ryan remains largely unknown outside those who closely watch politics – even to many in his own state outside his Janesville-centered congressional district. In Tampa this week, convention delegates sometimes confused him with Rep. Ron Paul of Texas.

Ryan, the youngest of four children, became interested in politics – and policy – early on, when he was an intern and aide on Capitol Hill, becoming a protege of the late Jack Kemp, a former Republican congressman and vice presidential candidate. In high school, Ryan was elected class president, which gave him a seat on the school board, his first taste of public office.

He worked briefly in the family construction business founded by his great-grandfather and moved back to his childhood neighborhood. He ran for Congress on a campaign opposing tax increases and supporting gun rights, won easily, and became the second-youngest member of the House of Representatives at the time. He grew up Catholic, and his religious beliefs have played an important part in his politics, guiding his positions on social issues such as abortion and gay marriage.

Democrats are betting that Ryan’s plan is a ripe target that could turn off the independent voters that determine elections.

“Paul Ryan really speaks to that kind of tea party, more libertarian wing of the Republican Party,” said Maryland Gov. Martin O’Malley, a top Democratic spokesman. “He’s been a real leader in the tea party Republican House in trying to get everything they can to slow our economy and our jobs recovery before the elections.’’

Obama campaign spokesman Robert Gibbs noted that some Republicans are running away from Ryan’s plans because they are so unpopular with Americans.

“I think it’s going to be fascinating to watch them dance around issues,” Gibbs said near the Republican convention site. “I think they’re going to have a lot of explaining to do in this convention. ... I think Paul Ryan has a lot to explain to the American people, because Mitt Romney basically outsources his party platform and budget to his vice presidential candidate, and now it’s now up to them to spend the next three days on how to make it palatable.”

But Republican activists in Tampa said Ryan should be able to easily appeal to independents, even Democrats. Some said they wished he had run for president, and that they liked Romney more after he selected Ryan as his running mate.

Wayne Papke, a self-described tea party Republican and delegate from North Dakota, said Ryan will be able to unify Republicans and Democrats because he has shown in Congress than can he can work with both parties.

“Paul Ryan is my hero,” said Papke, a financial adviser. “I wanted him and we got him. He’s going to unify. He’s a unifier. He’s done it in Congress and he has a lot of allies.”