State Sen. Tom McClintock (R), running in California’s open 4th district, is scheduled Wednesday to receive the endorsement of the U.S. Chamber of Commerce at an event in Sacramento that will feature an appearance by Rep. Dan Lungren (R-Calif.), according to the McClintock campaign.

McClintock and retired Air Force officer Charlie Brown (D) are vying to replace Rep. John Doolittle (R), who is retiring. The 4th district encompasses the suburbs and foothills east of Sacramento, and is solid Republican territory. Brown came within 3 points of ousting Doolittle in 2006.

Already, the U.S. Chamber of Commerce has endorsed former Senate aide Pete Olson (R), who is challenging Rep. Nick Lampson (D) in Texas’ majority-Republican 22nd district; and wealthy restaurateur Ed Tinsley (R), who is running for New Mexico’s open, conservative-leaning 2nd district. Tinsley is facing former Lea County Commissioner Harry Teague (D), who is also wealthy, in that race.