, a six-term senator , earlier had hinted he would run for re-election despite some criticism of his role in the controversial firings of U.S. attorneys . One of the prosecutors , David Iglesias , contends Domenici and U.S. Rep. Heather Wilson , R-New Mexico , wanted him to push harder on a corruption investigation of state Democrats before the 2006 midterm elections . Iglesias said he felt `` leaned on '' when Domenici called him to inquire about when indictments would be brought . The senator , who nominated Iglesias for the post , apologized for making the call but said he never pressured Iglesias . Domenici said he had complained to Justice Department officials about the pace of prosecutions in Iglesias ' office . Then-Attorney General Alberto Gonzales said Domenici had complained to him about Iglesias in the fall of 2005 , saying the U.S. attorney `` was in over his head . '' Iglesias , a Naval Reserve lawyer listed in a Justice Department evaluation as a `` diverse up-and-comer '' before 2006 , was told to resign that December . Domenici , 75 , was first elected to the Senate in 1972 and has n't faced
-LRB- CNN -RRB- -- Republicans ' tough task of taking back control of the Senate next year now looks even tougher . Sen. Pete Domenici , R-New Mexico , says he will retire at the end of his term . Republican Sen. Pete Domenici of New Mexico announced Thursday that he will not seek re-election . `` For the past 35 years my friends and neighbors have given me the honor of allowing me to serve them as their United States senator , '' he said . `` Who could ask for anything more ? Domenici joins three other Republican senators who also are retiring at the end of their terms next year . Democrats took back both houses of Congress last November , but hold thin majorities . In the Senate , they have a 51-49 margin . Their advantage in the House of Representatives is 233-202 . Of 34 Senate seats being contested next year , Republicans hold 22 . With the four senators retiring and four others facing difficult re-election bids , the numbers are stacked against GOP hopes of recapturing the upper chamber of Congress . Read more about the senators who are retiring '' Domenici