The U.S. Chamber of Commerce is launching ad buys for more establishment-aligned Republicans, including one former Democrat who recently switched parties.

The Chamber will run ads for Rep. Shelley Moore Capito (R) in the open West Virginia Senate race. It will also run ads for Rep. Mike Simpson (R-Idaho), who faces a tea party-backed primary challenger, and West Virginia state Sen. Evan Jenkins, who recently switched parties to challenge longtime Rep. Nick Rahall (D-W.Va.).

Earlier this week, the chamber launched ads for Senate Minority Leader Mitch McConnell (R-Ky.), who also faces a tea party primary opponent.

The proximity of the ad buys suggests an increasing desire by the chamber to back establishment-friendly candidates -- particularly ones who the party's right wing might not like and might face primary challenges. Increasingly in recent years, tea party groups have supported challengers to these kinds of Republicans, who haven't found similar support from outside groups.

Simpson is the first House incumbent to be targeted by the conservative Club for Growth this cycle. He faces attorney Bryan Smith.

Jenkins and Capito so far don't face quality primary challengers, but the Club for Growth has made it known that it doesn't much like Capito.

Update 1:35 p.m.: A reader notes that Jenkins is a former general counsel to the West Virginia Chamber of Commerce -- which makes his endorsement less-than-surprising.