There are generally two strategies in voting for a presidential candidate for a party:
1. Who can beat the opposing candidate?
2. Who do we want to be the president?
The first concern often relegates the second concern to a footnote, and sometimes results in choosing the strongest campaigner rather than the person who would be the best president.
In 2012, President Obama will almost certainly be the Democratic candidate for president. The 3rd-party candidates aren't likely to be significant in any way. That leaves the Republican candidate as the next big choice.
If you're interested, here's Huck's latest book: A Simple Government: Twelve Things We Really Need from Washington (and a Trillion That We Don't!)