I’d expect the sniping between the Romney and Thompson campaigns to get worse before it gets better. They are both competing for the same slice of voters, and they each would benefit tremendously from the other being knocked out of the race. Thompson has the support in the national polls and the potential to break through in the South; Romney has solid leads in key early states and has seen some progress in his national numbers. Their combined presence in the race, however, is making it easier for Giuliani to lead in unlikely places like South Carolina.

Similar competition between Pat Buchanan and Phil Gramm in 1995-96 led to the former bloodying the latter in Louisiana and then finishing him off in Iowa. But such infighting can backfire as well. In 2000, Steve Forbes trained a great deal of his fire on the electorally irrelevant Gary Bauer, who peaked with 8 percent in Iowa, while the nomination contest was turning into a Bush-McCain race.