Republicans will have former Rep. Artur Davis speaking at their national convention this week — the man who served as Barack Obama’s national co-chair in 2008 and seconded his nomination at the Democratic convention that year. Democrats now have their answer, a prominent former Republican officeholder who will speak at the Democratic convention in Charlotte next week: Florida’s former Republican Gov. Charlie Crist will be a speaker at the Democratic National Convention. An official with President Barack Obama’s campaign said Sunday that Crist will speak at next week’s convention in Charlotte, N.C., but the day hasn’t been worked out. Actually,...