How important are five votes out of seven million Washingtonians? The vote of just five state Supreme Court Justices could be the difference between Washington maintaining its competitive advantage of not imposing state income taxes and the eight decade old dam of legal precedent preventing these types of taxes being torn down. 

Since 1930 the state Supreme Court has issued numerous opinions interpreting Article 7, Sections 1 and 2 of the state's constitution to require taxation of property, including income, to be uniform and limited to 1%. While there is no ban on enactment of a uniform income tax limited to 1%, under eight decades of legal precedents, a progressive or targeted income tax in Washington is unconstitutional.

While the state Department of Revenue says that description of Washington's income tax ban is accurate, it provided this qualifier in an email: 

Revenue as an agency doesn't take a position on whether the current court would follow the old precedents and hold a graduated or targeted income tax unconstitutional.

It is very concerning that state's tax agency isn't sure "whether the current court" feels bound to follow eight decades of case law. That said, based on some of the court's recent rulings, taxpayers are left to wonder whether they are still truly protected from an income tax or are just five justices away from seeing one imposed. 

That said, former state Supreme Court Justice Phil Talmadge provides this analysis of whether the eight decades of case law banning a graduated income tax in Washington is still sound: 

Washington law is unambiguous. Income is property. Beginning in Aberdeen Savings and Loan Association v. Chase, and continuing through a series of cases, the Washington Supreme Court has held that income is property. As such, this tax is subject to the provisions of the so-called uniformity clause, article 7, section 1 of the Washington Constitution, which provides that all taxes ‘shall be uniform upon the same class of property within the territorial limits of the authority levying the tax...’

Moreover, article 7, section 2 of the Washington Constitution establishes the upper limit upon ad valorem property taxes. That constitutional restriction essentially limits any property tax to no more than one percent of the value of the property . . .

The proponents of a graduated net income tax in Washington have vociferously argued that these older cases are no longer viable, because they allegedly rely on United States Supreme Court precedent that no longer finds that income-based taxes constitute taxes on property. This argument finds full flower in a 1993 law review article [by law professor Hugh Spitzer]. The essence of the argument advanced by Mr. Spitzer is found in the Context section of Initiative 1098.

However, since 1993, the Washington Supreme Court has been confronted with cases in which the continuing validity of the ‘income as property’ cases was questioned and has rejected the argument articulated in the Spitzer law review article.

Even without a full frontal assault attempting to overturn eight decades of precedent, creative income tax proponents continue to try to rename income tax proposals as excise taxes to try to get them through the door (see this year's debate on a capital gains income tax). 

So what should Washingtonians do if we want to ensure we maintain a court proof ban on all types of income taxes? 

Consider the example of what voters in Tennessee did last year. Like Washington, Tennessee doesn't tax income but prior to 2014 the lack of an income tax was a policy decision, not prohibited. Wanting to make sure citizens and businesses could have the peace of mind an income tax wasn't just a legislative session away lawmakers asked voters to approve a constitutional amendment banning income taxes. 

Sponsor of the Tennessee income tax ban constitutional amendment Sen. Brian Kelsey told Business Week:

This is going to help us bring in jobs to Tennessee. We can say not only do we not have an income tax, but we'll never have an income tax.

66% of Tennessee voters agreed in 2014 approving the constitutional ban on income taxes. 

Unless we want to leave it up to a mere five votes on the state Supreme Court in hopes they'll follow eight decades of precedent, Washingtonians should encourage lawmakers to let the people act on a constitutional amendment making the state's ban on income taxes crystal clear and immune from judicial tinkering. 

Additional Information
Attorney General Opinion No. 105 (1974): Constitutionality of income tax
Attorney General Opinion No. 79 (1972 - informal): Constitutionality of single rate income tax
Legal Analysis by Former State Supreme Court Justice says I-1098 Income Tax is Unconstitutional
Proposed capital gains tax is likely an unconstitutional income tax and would be an unreliable revenue source
"Choose Washington" - no capital gains taxes