Meet the definition of insanity. Bob Ferguson, the Democratic governor of Washington, yesterday signed into law the state's first-ever income tax: a "millionaires' tax" of 9.9 percent on adjusted gross income above $1 million. Overnight, Washington has gone from boasting no income tax to having the fifth-highest top marginal rate in the nation, tied with Oregon.

Given its progressive politics, it's shocking that Washington did not already have an income tax. That is thanks to a 1933 decision by the Washington Supreme Court, which held that a progressive income tax violated the state's constitution. In nearly a century since then, voters ...

© National Review