1. Romney carefully vetted all his candidates for running mate, in stark contrast to McCain's example. Ryan won't outshine the top of the ticket and is unlikely to go rogue.
2. Ryan will energize the base by bringing undisputable conservative credentials for Tea Partiers who don't fully trust Romney.
3. Ryan plants the ticket solidly on the right because, unlike Romney, he has strong conservative creds on guns, abortion, health care reform, warrantless wiretaps, gay rights.
4. He's a budget policy wonk who can help Romney keep the focus on the economy and the need to cut entitlements and eliminate government programs. Romney has called the Ryan budget plan "marvelous."
5. Ryan brings two decades of Washington Insider and legislative experience that Romney lacks.
6. He has a base in the House GOP caucus's younger and more conservative members who dominate that body.
7. He is intelligent, articulate, energetic, personable and a good debater
8. He is strong where Romney is weak – details. He will focus the debate on spending priorities.
9. His youth, 42, complements Romney's age, 66.
10. He can carry a tune.