Fed. R. Evid. 607
Who May Impeach a Witness
Any party, including the party that called the witness, may attack the witness’s credibility.
( Pub. L. 93–595, § 1 , Jan. 2, 1975 , 88 Stat. 1934 ; Mar. 2, 1987 , eff. Oct. 1, 1987 ; Apr. 26, 2011 , eff. Dec. 1, 2011 .)