Fred Thompson's First Cattle Call...

Ex-Sen. Fred Thomson is on the verge of committing to his first major Republican cattle call.

An Indiana Republican says that Thompson is planning to announce that he'll attend the Midwestern Republican Leadership Conference in Indianapolis, which begins on Aug. 24.

(Ex-Gov. Mitt Romney is attending; Sen. John McCain is likely to attend; Ex-NYC Mayor Giuliani is tbd).

The MRLC gathers more than 1,000 top Midwestern Republicans in one place and is a compliment to the Southern Republican Leadership Conference, at whose straw poll Mitt Romney pulled a surprise second place showing in 2006. The last time the biennial conference was held in Indianapolis, the star of the show was a Texas Gov., George W. Bush.