Lawmakers approved a rule requiring same-sex couples who are legally married in other states but live in Idaho to file their state income taxes separately - even though they can file their federal taxes jointly.

The House Revenue and Taxation Committee made the decision Tuesday over objections from same-sex couples who said this would boost their annual tax payments, complicate filings and be a sign Idaho doesn’t respect their unions.

Republican lawmakers were joined by one Democrat, Rep. Caroline Meline of Pocatello, in backing the rule of the Idaho State Tax Commission.

The rule is now final.

The supporters said they were following Idaho’s statutes and Constitution.

However, the rule has already been singled out in a constitutional challenge in U.S. District Court seeking to topple Idaho’s 2006 gay-marriage ban.