The 14th Amendment has been held to apply the First Amendment against the states. And even in the likely event that incorporation gets overturned, most state constitutions have their own establishment clauses.

What bbanyc said, for details see:

https://en.wikipedia.org/wiki/Incorporation_of_the_Bill_of_R...

and

http://leg.wa.gov/LawsAndAgencyRules/pages/constitution.aspx