Wash. Rev. Code § 2.28.010
Every court of justice has power-(1) To preserve and enforce order in its immediate presence. (2) To enforce order in the proceedings before it, or before a person or body empowered to conduct a judicial investigation under its authority. (3) To provide for the orderly conduct of proceedings before it or its officers. (4) To compel obedience to its judgments, decrees, orders and process, and to the orders of a judge out of court, in an action, suit or proceeding pending therein. (5) To control, in furtherance of justice, the conduct of its ministerial officers, and of all other persons in any manner connected with a judicial proceeding before it, in every matter appertaining thereto. (6) To compel the attendance of persons to testify in an action, suit or proceeding therein, in the cases and manner provided by law. (7) To administer oaths in an action, suit or proceeding pending therein, and in all other cases where it may be necessary in the exercise of its powers or the performance of its duties.
RCW 2.28.010
Compelling attendance of witnesses: Chapter 5.56 RCW.
Oaths, who may administer: RCW 5.28.010.