Paul Mirengoff @ Powerline:
Former Florida Governor Charlie Crist will speak at the Democratic Convention on a day yet to be determined. Crist, formerly a Republican, has already endorsed President Obama.
A convention address by a prominent politician with ties to the other party can be effective. Zell Miller brought down the house, and likely swayed some undecided voters, with his scathing attack on the Democrats in 2004. Joe Lieberman, the anti-Zell Miller in a way, delivered an effective speech on behalf of his friend John McCain in 2008.
I don’t know what kind of a speaker Crist is, but there is an important difference between him and Miller/Lieberman. Miller was a winner. He won easy election to the Senate in 2000. Lieberman was also a winner, having defeated a left-wing Democrat and a Republican in 2006 to hold his Senate seat.
Crist, by contrast, is a loser. In 2010, he dropped out of the Republican Senate primary because he had no shot at defeating Marco Rubio. He then ran as an independent. Rubio trounced him, 49 percent to 30 percent.
The fact that Crist lost gives rise to the suspicion that his endorsement of Obama represents sour grapes. This suspicion gains strength from the fact that Crist in the past has been quite critical of Obama.