As the lead defense counsel in a 2010 impeachment trial in the Senate, I can say from experience that I would much prefer a client to be indicted first, rather than impeached. To start with, a defendant under indictment can avail himself of myriad constitutional and procedural protections that aren’t available in the impeachment process. In impeachment proceedings, the federal rules of evidence on issues ranging from hearsay to chain-of-custody are discretionary, not binding. The ability to call witnesses, presentation of evidence and discovery are all left to the Senate’s judgment. Then there is the jury. There is no voir dire or vetting; the defense is stuck with 100 elected, career politicians who, in many instances, have already made public statements regarding your client.
Conversely, an indictment comes with a formal grand jury determination and set stages of the legal proceedings, from arraignment to pretrial to a trial with a real judge. Defense motions to address violations of the defendant’s First, Fourth, Fifth and Sixth Amendment rights are routinely heard and carefully addressed. Firm evidentiary rules — both statutory and constitutionally based — guarantee the timely disclosure, to defense lawyers, of evidence and witnesses known to government prosecutors. At trial, judges control witnesses to avoid prejudicial statements or testimony related to excluded evidence.