Wash. Rev. Code § 10.40.170
The plea of guilty can only be put in by the defendant himself or herself in open court.
[ 2010 c 8 s 1041; Code 1881 s 1056; RRS s 2110. FORMER PART OF SECTION: Code 1881 s 1057; RRS s 2111, now codified as RCW 10.40.175.]