Club for Growth picks Neumann over Thompson in Wisconsin GOP Senate race

Club for Growth, which had previously endorsed Neumann, also released an advertisement titled “Change.” The ad repeats the charges laid out in the press release, and goes on to trumpet Neumann as “Wisconsin’s most conservative congressman in decades."

A new Public Policy Polling survey showed Hovde leading the GOP primary race with 28 percent support. Thompson, who once maintained a big lead in the GOP race, was tied with Neumann at 25 percent. 

Neumann previously served in the House representing Wisconsin's 1st Congressional District from 1995-1999 before losing to former Sen. Russ Feingold (D-Wis.). After a hiatus from politics he chose to run for governor in 2010, but was defeated by Scott Walker in the GOP primary.

If Neumann emerges from the primary as the victor, his likely opponent would be Democratic Rep. Tammy Baldwin.

The Club for Growth recently endorsed former Texas Solicitor General Ted Cruz, who won Tuesday's GOP Senate primary in Texas.