UPDATE:  See our story on Nixon’s announcement and reaction to it here.

Gov. Jay Nixon today will issue an executive order directing the Missouri Department of Revenue to accept the jointly-filed state tax returns of all legally married couples, including same-sex couples legally married in other states, who file joint federal tax returns as required under Missouri law.

“Missouri is one of a number of states whose tax code is directly tied to that of the federal government and under Missouri law, legally married couples who file joint federal tax returns with the IRS must also file joint state returns with our state Department of Revenue,” Gov. Nixon said. “As a result, accepting the jointly-filed state tax returns of all legally-married couples who file federal returns is the only appropriate course of action, given Missouri statutes and the ruling by the U.S. Department of the Treasury.”

The U.S. Department of the Treasury and the Internal Revenue Service ruled in August that legally married same-sex couples would be treated as married for federal tax purposes, regardless of where the couple lives. The Treasury’s ruling implemented federal tax aspects of the June 26th Supreme Court decision invalidating a provision of the 1996 Defense of Marriage Act.

Missouri tax law states that couples filing a “joint federal income tax return shall file a combined return,” and that any terms used in Missouri tax law shall have the same meaning “as when used in a comparable context in the laws of the United States relating to federal income taxes.”

The Governor said his executive order applies only to the specific issue of tax filing status and does not in any way authorize or sanction same-sex marriage in Missouri, which the state’s constitution does not recognize.

Under the executive order, any federal exemptions or deductions that married couples can receive that are reflected in their federal adjusted gross income will therefore be reflected on their state tax return. However, the order does not change the eligibility for any state-level exemptions, deductions or credits.