President George W. Bush today said Agriculture Secretary Mike Johanns will step down to consider a bid for a US Senate seat from Nebraska.
Mr Johanns is the latest senior administration official to leave in recent months, following former attorney general Alberto Gonzales and close Bush confidant and political strategist Karl Rove.
Mr Bush said it was up to Mr Johanns whether he would seek another political office but added that he thought he would "make an outstanding member of the United States Senate."
Deputy Agriculture Secretary Charles Conner will serve as acting secretary.