Here's a little C/P for you.....

I had to go find it because, you know, I might not be right....

In 1932, following passage of the only income tax initiative to be approved by state voters, the
Washington Supreme Court declared that for purposes of taxation, income is defined as a class of
property. Article IV of the Washington Constitution states that all taxes shall be uniform upon the
same class of property. Therefore, any income tax proposal either would have to be consistent with
the Constitution’s uniformity restrictions, or would likely require a constitutional amendment in order to
be implemented.

There is a chance that today's legislature may over rule the concept of income being property...but they haven't yet, Mr. BMI.