A Missouri house republican wants to impeach Democratic Governor Jay Nixon over his order that the state accept joint tax returns from legally married same sex couples. A resolution filed Thursday by Parkville Republican Nick Marshall states Nixon is guilty of “willful neglect of duty and misconduct in office.” Missouri’s constitution states marriages must be between a man and a woman to be valid and recognized. Missouri’s tax code is tied to the federal government and Nixon said couples filing joint federal returns also must file joint state returns. Federal agencies determined legally married. Same- sex couples would be treated as married for tax purposes regardless of residence.