1. His budget plans include big cuts, and there's ample room for Democrats to continue with their "Romneyhood narrative." The nonpartisan Center on Budget and Policy Priorities
estimates 62 percent of Ryan's cuts are to programs for the poor.
2. Ryan's budget proposals have included big changes to Medicare - including gradually replacing the program with a voucher program for private health care, and gradually raising the retirement age. That could scare older Americans, a crucial voting bloc.
3. He voted for the Troubled Asset Relief Program, or TARP. While a lot of other Republicans did too, and it was proposed by the Bush administration, some have viewed it as a rejection of the conservative economic values Ryan and hard-line fiscal conservatives espouse.
4. He's easily pegged as Washington insider. He's been in Congress since 1999, and before that he worked as a congressional staffer. Congressional approval ratings are abysmally low- a recent CBS News/NY Times
poll showed that only 12 percent of voters approve of the way Congress is doing its job.
5. This is both a pro and a con to Ryan, depending on who you ask, but he's notably further to the left on the issue of lesbian, bisexual, gay and transgender rights than the base of the party. He broke with a lot of his party to support the Employee Non-Discrimination Act in 2007. He explained his reasoning for the vote in this way:
"They [his gay friends] didn't roll out of bed one morning and choose to be gay. That's who they are."