MADISON, WI (WTAQ) - Just when you thought it was safe to watch TV again, a new round of political attack ads appears to be in the works. 

Tommy Thompson’s U.S. Senate campaign says it expects a flurry of attack ads, after a new Marquette poll gave the former governor an 18 point lead over the nearest of his three Republican challengers.

The conservative Club for Growth is backing former Congressman Mark Neumann, saying he’s the true conservative in the race. The group has also questioned Thompson’s conservative credentials, and it ran ads attacking the former governor last summer before he entered the Senate field.

Barney Keller of the Club for Growth says voters have not focused on the Senate race because they’re still getting over the Walker recall effort. But once they start paying attention, he says Thompson’s support will vanish.

Keller claims Thompson’s lead in the Marquette poll is due only his name recognition and, “Republicans already suspect that Tommy Thompson isn’t a true conservative.”

Thompson, Neumann, Jeff Fitzgerald, and Eric Hovde will square off in an August 14th primary, with the winner to face Democrat Tammy Baldwin in November for the right to replace retiring Senator Herb Kohl.

The Marquette poll, released Wednesday, shows Thompson with a 34-16 percent lead over Neumann among likely Republican voters. Hovde had 14 percent and Fitzgerald 10.