@TomD8 wrote:
Per IRS Publication 501, you must be "considered married" in order to file a joint return. Here's how the IRS defines that:
Right, but the devil is in the details.
For 3, You are married and living apart but not legally separated under a decree of divorce or separate maintenance.
The tax courts have ruled on this several times and have never ruled (that I found) that someone who has a legal separation actually qualifies as "legally separated under a decree of divorce or separate maintenance." For example, if you have a temporary support order that will be finalized when the divorce is final, that temporary order is not a final decree of separate maintenance, and does not qualify the spouses to be legally unmarried. Or, if under state law you are separated but could reconcile (that is, reconciliation is legal and possible, no matter how unlikely) then the separation is not final and you are not unmarried for purposes of income taxes (other than the special rules for HOH).
Likewise, 4. "You are separated under an interlocutory (not final) decree of divorce" no longer exists in the US as a practical matter. A legal separation agreement, even if supervised by the courts, is not an interlocutory decree of divorce.
As I read the court cases, it seems there was a type of marital separation that was more common before WWII, where the spouses would not be "divorced" (because divorce was seen as immoral and was against many people's religious beliefs) but where there was a need for a legally enforced separation that was permanent and final. (In fact, this type of separation is still on the books in NY but no one uses it any more, because it costs the same as a divorce, has the same trauma and other costs, but leaves the parties without the ability to remarry.)
The Tax court cases that deal with the idea that people can be "considered unmarried" prior to a final divorce focus a lot on the idea of finality. If a support order is not final, or the separation is not final under state law, then the parties are not considered unmarried.
This is, of course, my own perspective, as someone who paid many thousands of dollars extra during my separation, and did a lot of research on the meaning of "considered unmarried" and the relevant court cases. But I am not a lawyer, and I suggest that if anyone who is legally separated wants to file as single instead of MFS, they consult a tax attorney in their state. And to the original OP, because of what the tax court cases have said about separation, I believe they are allowed to file MFJ as long as they both agree.
