Most of the time a LEGAL marriage has nothing to do with a church/minister/religion at all. It's 100% a 'state' thing for filing of taxes, courtroom protections, power of attorney etc. Getting married in a church doesn't grant any of those things. Having a piece of paper from your 'state' is what makes it legal in the government's eyes. If the government won't sign off, you're not LEGALLY married, just socially.