Americans for Prosperity [3], the conservative front group [4] founded by oil billionaire David Koch [5] that funds the Tea Party [6], quietly worked in the background to undermine Democratic candidates in Washington state. Like AFP's national office, AFP Washington (AFPW) does not disclose its donors. The group sent out a mailer opposing State Senator Rodney Tom, a Democrat who represents the areas of Kirkland, Medina and Bellevue, Washington. An earlier AFPW mailer targeted State Senator Eric Oemig, who also represents Kirkland. While federal rules allow the AFP's national office to conceal its donors, Washington state laws mandate disclosure at the state level. Despite this, AFPW did not register with Washington's Public Disclosure Commission, and has given no hint of who funded the attack ads. One week prior to election day, the Sierra Club [7]'s Cascade chapter filed a complaint against AFPW over its anonymously-funded, targeted attacks.