Washington Revised Code Title 9A. Washington Criminal Code § 9A.72.050. Perjury and false swearing--Inconsistent statements--Degree of crime

(1) Where, in the course of one or more official proceedings, a person makes inconsistent material statements under oath, the prosecution may proceed by setting forth the inconsistent statements in a single count alleging in the alternative that one or the other was false and known by the defendant to be false. In such case it shall not be necessary for the prosecution to prove which material statement was false but only that one or the other was false and known by the defendant to be false.

(2) The highest offense of which a person may be convicted in such an instance as set forth in subsection (1) of this section shall be determined by hypothetically assuming each statement to be false. If perjury of different degrees would be established by the making of the two statements, the person may only be convicted of the lesser degree. If perjury or false swearing would be established by the making of the two statements, the person may only be convicted of false swearing. For purposes of this section, no corroboration shall be required of either inconsistent statement.