I spoke with Rep. Terry Nealey, ranking Republican on the House Finance Committee, this morning for an update on the letter lawmakers sent to the Attorney General asking him to intervene in the Seattle income tax lawsuit. Rep. Nealey told me the Attorney General is currently undecided if he will defend state law banning a local income tax. Discussing the importance of lawmakers' request, Nealey said in a September 27 press release:

“This lawsuit is very clearly not just about Seattle’s ordinance. There is a party to the suit who now seeks to invalidate a state law that protects all state taxpayers and promotes a level playing field for commerce. It is the attorney general’s responsibility to represent the state in all cases in which the state has an interest. EOI’s intervention would open this to broader jurisdictions and put the state’s interests at stake. Therefore, we are asking the attorney general to vigorously defend the constitutionality of state law that prohibits imposition of local income taxes.”

On October 6 the Attorney General sent lawmakers this reply letter:

“Thank you for your letter of September 26, requesting that my office intervene in a superior court case in which plaintiffs challenge a City of Seattle ordinance. The basis for your request is that a party has intervened in that lawsuit and seeks invalidation of a state statute.

As you know, our office defends the constitutionality of statutes when the state or a state agency is sued. That is not the situation here. Intervening requires the state to become a party and incur the expense of litigation. Consequently, where the challenge to a statute arises in a lawsuit to which the state is not a party, the Attorney General's Office rarely intervenes.

My office is analyzing this issue. When a decision is made, we will let you know.”

According to Rep. Nealey he spoke yesterday with the Attorney General’s office and was told they are still discussing whether to intervene or file an amicus. Rep. Nealey told me he will continue to follow up with the Attorney General for an update as to whether he will defend state law that bans local income taxes.

RCW 43.10.030 says:

“The attorney general shall: (1) Appear for and represent the state before the supreme court or the court of appeals in all cases in which the state is interested.” (Also see RCW 7.24.110)

The Walla Walla Union Bulletin wrote an editorial encouraging the Attorney General to defend state law (also reprinted in the Spokesman Review):

"Ultimately, it’s about making sure Seattle (or any local government) can’t circumvent the state constitution. As such, the place to take a stand is when the law is ignored.

The attorney general should fight this attempt by Seattle to impose taxes that are not allowed by state law."

During a July 18, 2017 speech to the Washington State Labor Council the Attorney General highlighted that his office has a duty to defend state law and defeat unlawful acts. 

The Attorney General has filed and/or intervened in several federal lawsuits since the City of Seattle enacted the local income tax on July 10. To date, however, he has not expressed an opinion on if the decision by City of Seattle to impose a local income tax was lawful. 

Additional Information
Legal Brief: Seattle income tax is "subterfuge"
Timeless advice from WA Supreme Court on income taxes