liberal champion , 82 , has spoken widely about gay rights .
she even officiated at a same-sex ceremony in august 2013 .
opponents have said it makes her unfit to rule on upcoming case .
obergefell v. hodges will be heard by nation 's top court from this week .
case will decide whether all states have to allow gay marriages .
even if not , could be forced to recognize gay marriages in other states .
ginsburg is in liberal minority in the supreme court .
but conservative anthony kennedy often votes in favor of gay rights .