The Washington constitution defines equality as treating people "without distinction or preference on account of race, color, caste, or sex."
Those concepts are often stretched to cover much more than that since the original idea is making no differentiation of citizens and their rights at all.
You can even see in Article I, Section 19 a text that says <em>"All Elections shall be free and equal, and no power, civil or military, shall at any time interfere to prevent the free exercise of the right of suffrage."</em>
There are other examples in Article 1 and 7 of claims for equality.
Article 7 Section 2<em> "The legislature shall provide by law a uniform and equal rate of assessment and taxation on all property in the state, according to its value in money, and shall prescribe such regulations by general law as shall secure a just valuation for taxation of all property, so that every person and corporation shall pay a tax in proportion to the value of his, her, or its property; Provided, that a deduction of debts from credits may be authorized: Provided, further, that the property of the United States and of the state, counties, school districts and other municipal corporations, and such other property as the legislature may by general laws provide, shall be exempt from taxation"</em>
And Article 19 Section 1<em> "Equality of rights and responsibility under the law shall not be denied or abridged on account of sex."</em>
