san francisco california file lawsuit wednesday trump administration plan construct wall along border mexico add obstacles face one republican president key campaign promise president donald trump insist mexico would pay build wall experts say could cost 22 billion take three years complete mexico refuse pay trump say since take office january wall initially need u.s. fund find way make mexico ultimately pay democrats u.s. congress however firmly oppose border wall least democratic senators would need vote inclusion spend package democratic attorneys general include california xavier becerra sue trump administration range issue border wall lawsuit file san diego federal court allege trump wall violate federal environmental standards well constitutional provision regard separation power state right representatives u.s. justice department decline immediately comment case lawsuit ask judge stop administration build wall demonstrate compliance environmental laws issue order department homeland security waive federal guidelines order facilitate project last month trump administration say select four construction company build concrete prototypes wall 30 feet meter tall 30 feet wide test san diego california sue trump administration border wall