The Wall Street Journal has an excellent suggestion for the first witness in the current Schumer-generated kerfuffle:

As it happens, Mrs. Clinton is just the Senator to walk point on this issue of dismissing U.S. attorneys because she has direct personal experience. In any Congressional probe of the matter, we'd suggest she call herself as the first witness--and bring along Webster Hubbell as her chief counsel.

As everyone once knew but has tried to forget, Mr. Hubbell was a former partner of Mrs. Clinton at the Rose Law Firm in Little Rock who later went to jail for mail fraud and tax evasion. He was also Bill and Hillary Clinton's choice as Associate Attorney General in the Justice Department when Janet Reno, his nominal superior, simultaneously fired all 93 U.S. Attorneys in March 1993. Ms. Reno--or Mr. Hubbell--gave them 10 days to move out of their offices.