BOISE, Idaho (AP) — Idaho aims to require same-sex couples who are legally married elsewhere to recalculate their federal Internal Revenue Service filings before filing state taxes.

Tax Commission spokeswoman Liz Rodosovich said Thursday the agency altered its 2013 income tax forms following June's U.S. Supreme Court decision invalidating parts of the federal Defense of Marriage Act. That prompted the IRS to rule legally married same-sex couples in states that recognize their marriages will be treated as married for federal tax purposes. Now, Idaho's rules potentially require extra bookkeeping.

Those who file a joint federal return as a same-sex couple must file an Idaho return as single or head of household. Then, they must recalculate their federal tax return, as if they'd used single or head of household status, before filing with the state.

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