Former Minnesota Gov. Tim Pawlenty (R) and former Sen. Rick Santorum (R-Pa.) will participate in a Values Voter bus tour that will stop in 22 Iowa cities next week in the lead-up to the presidential debate and straw poll in Ames.

The Family Research Council, National Organization for Marriage and Susan B. Anthony List, three socially conservative groups, have organized the tour.

Both Pawlenty and Santorum need strong showings in the Ames straw poll on Aug. 13 to be considered top-tier candidates. Rep. Michele Bachmann (R-Minn.), currently considered the front-runner to win the straw poll, plans to join the tour but is still working out logistics, according to a spokesman for the tour organizers.

The tour will also be joined by Rep. Steve King (R-Iowa) and Rep. Louie Gohmert (R-Texas), two of Bachmanns closest allies in Congress. The three co-sponsored a bill to oppose raising the debt ceiling in July.