Md. Rule 5-607
Rule 5-607. Who May Impeach
The credibility of a witness may be attacked by any party, including the party calling the witness.
Committee note: This Rule eliminates the common law “voucher” rule. It does not permit a party to call a witness solely as a subterfuge to place an otherwise substantively inadmissible statement before the jury. It is not intended to otherwise affect existing law concerning the court's discretion to control direct and cross-examination.