Mitt Romney's selection of Paul Ryan was no surprise. He had been in the top three likely candidates for weeks.
Traditionally a vice-president is selected to "balance the ticket". Often this is geographically-based. A candidate who is running poorly in a certain state or area will pick someone who is stronger to share the ticket. Jimmy Carter who was a moderate southern governor chose Mondale who was a liberal northern congressman. Other times they choose their strongest primary challenger. That is why Kennedy chose Johnson and Reagan chose Bush.
A desperate candidate will choose someone to add excitement to the ticket. Mondale and McCain both chose inexperienced women. Gore chose a Jewish running mate.
A few candidates choose as if the election was a formality. They choose someone who (supposedly) will help them govern. The last two vice-presidents (Cheney and Biden) fall into that category. Both were supposed to help a new president adjust to governing in Washington.
Ryan is a variation of the traditional pick. Romney needs strong support from his base so he chose someone whose credentials as a fiscal conservative are impeccable. This will fire up the primary voters who went for ABR (anyone but Romney). Ryan is also a stronger choice than any of Romney's primary challengers. All of them were deeply flawed. Gingrich is probably the only one who might be an asset and I doubt that he wants the job.
Ryan's biggest strength is also his biggest weakness. He is the embodiment of the House budget. Democrats already won a special election with an ad showing a Ryan-lookalike literally throwing someone in a wheelchair over a cliff. The Democrats will charge that Romney and Ryan are trying to eliminate Medicare as we know it. This is a dishonest attack since Medicare as we know it has to be reformed in the near future before it runs out of money. The Democrats know this but consider it a winning issue to pretend that there is no looming crisis and claim that they will save it.
Romney's defense against these attacks should be to point out that Medicare cannot survive without major changes and to challenge the Democrats to identify how they plan to save it. They need to hit Obama hard for "kicking the can down the road".
In the next few months we will see variations on the "granny over the cliff" ad. Romney and Ryan need to be ready to hit back hard on this issue. Romney needs to say something like, "What I paid in taxes is meaningless compared to the impending crisis in Medicare, Medicaid, and Social Security. President Obama needs to tell the American people how he will addresses these issues instead of distracting the voters with class warfare."
With a strong running mate and a strong attack, Romney has a good shot at winning. If he does not have his attack prepared then he will loose.