Respondent's Brief - Washington State Courts

To be relevant, evidence must meet two requirements: (1) the
evidence must have a tendency to prove or disprove a fact (probative
value), and (2) that fact must be of consequence in the context of the other
facts and the applicable substantive law (materiality)." State v. Rice, 48
Wn, App. 7, 12, 737 P.2d 726 (1987). Relevant " evidence encompasses
facts that present both direct and circumstantial evidence of any element
of a claim or defense." Rice, 48 Wn. App. at 12. "Facts tending to
establish a party's theory of the case will generally be found to be
relevant." Id, citing ( State v, Mak, 105 Wn. 2d 692, 703, 718 P.2d 407
1986)).
It is well settled in Washington that evidence of drug use is
admissible to impeach the credibility of a witness ifthere is a showing
that the witness was using or was influenced by the drugs at the time of
the occurrence which is the subject of the testimony."' State v. Thomas,
150 Wn.2d 821, 863-64, 83 P.3d 970 (2004)( quoting State v. Russell, 125
Wn.2d 24, 83, 882 P.2d 747 (1994)) emphasis ( added). See State v. Clark,
48 Wn. App. 850, 863, 743 P.2d 822 (1987). The reason is that the effect
of drugs used at the time of an incident may substantially impeach a
witness's recall of that incident. See State v. Kendrick, 47 Wn. App. 620,
634, 736 P.2d 1079 (1987). Thus, fJor "[ evidence of drug use to be
admissible to impeach, there must be a reasonable inference that the
witness was under the influence of drugs either at the time of the events in
24 - optest-prosm iscsptriakmcdan iel. doc