Sen. Pete Domenici (R), the longest-serving Senator in New Mexico history, is expected to announce tomorrow that he will not seek a seventh term in 2008, according to multiple sources on and off Capitol Hill.

Domenici, 75, has been in declining health in recent years and has been the object of retirement rumors for several months. His retirement would put another safe Republican seat in play and could attract all three of New Mexico’s House Members into the race.