Missouri has a constitutional amendment banning same-sex marriage, but unlike other states with similar amendments, it appears that couples in same-sex marriages who need to file a Missouri tax return can file those returns as married.
Missouri’s tax laws say that taxpayers must use the same filing status on their Missouri return as they use on their federal return. This puts the tax law in conflict with the constitution when it comes to same-sex married couples. (Remember, a same-sex married couple can file their federal taxes as married — regardless of the state they live in.)
Other states with similar conflicts between tax law and the state constitution have said couples in same-sex marriages CANNOT file state taxes as married because the constitution trumps the tax law. See Nebraska, for example.
However, Missouri Governor Jay Nixon last week issued an executive order that decrees that couples in same-sex marriages can file their Missouri tax returns as married.
Kay Bell at the Don’t Mess With Taxes blog has more coverage here.