In most states, you cannot hold a civil union and a marriage to the same person at once, because marrying your civil union partner either converts the civil union into a marriage or dissolves it automatically. Vermont is the main exception, where the two statuses can technically coexist. But even there, keeping the civil union alongside the marriage adds nothing: marriage already provides every state-level right a civil union offers, plus more than a thousand federal protections that civil unions have never carried.
What a Civil Union Gives You and What It Doesn’t
A civil union is a state-created status that grants many of the same rights as marriage under that state’s law, including inheritance protections, hospital visitation, shared property ownership, medical decision-making, and parental rights. At the state level, it was designed to mirror marriage closely.
Marriage is recognized by both state and federal governments, and that federal recognition is the dividing line. The Respect for Marriage Act, signed in 2022, requires every state to give full faith and credit to a marriage valid where it was performed, regardless of the sex, race, or ethnicity of the spouses.1Congress.gov. H.R.8404 – Respect for Marriage Act Civil unions got no equivalent federal portability. Cross a state line with one and the new state may not recognize your relationship at all.
Federal Benefits a Civil Union Does Not Reach
The gap isn’t theoretical. It shows up on tax returns and benefit statements.
The IRS explicitly excludes civil unions from the definition of marriage for federal tax purposes. Revenue Ruling 2013-17 states that “spouse,” “husband,” and “wife” do not include individuals in a civil union, whether the couple is same-sex or opposite-sex.2Internal Revenue Service. Rev. Rul. 2013-17 Civil union partners cannot file joint federal returns, claim spousal deductions, or transfer assets between each other using the unlimited marital deduction for gift and estate tax.
Social Security follows a similar pattern. The agency says some people in non-marital legal relationships like civil unions “may qualify” for spousal or survivor benefits if they meet certain requirements, but the path is narrower and less certain than it is for spouses.3Social Security Administration. Do I Qualify for Benefits as a Spouse if I Am Now in, or the Surviving Member of, a Civil Union or Domestic Partnership? Married spouses have clear statutory eligibility.
The Department of Labor takes the same position for employer-sponsored retirement and health plans governed by federal law. Its 2013 guidance specifies that “spouse” and “marriage” do not include individuals in a civil union or domestic partnership, even when state law grants those relationships the same rights as marriage.4U.S. Department of Labor. Technical Release No. 2013-04 A self-insured employer plan is not required to extend spousal benefits to a civil union partner. Federal immigration law also recognizes marriage but not civil unions for sponsorship.
Where Both Statuses Can Coexist and Where They Can’t
The rules vary sharply by state.
Connecticut, Delaware, New Hampshire, and Rhode Island converted all existing civil unions into marriages by operation of law. If you had a civil union in one of those states and did nothing, you are already married and the civil union no longer exists as a separate status.
Hawaii dissolves the civil union automatically when you marry your partner. Illinois allows voluntary conversion: once you marry or convert, the civil union ends and you hold only a marriage.5Social Security Administration. Social Security Legislative Bulletin 117-12 – The President Signs H.R. 8404, the Respect for Marriage Act Illinois also waives the marriage license fee for couples converting from a civil union.
Vermont is the outlier. When Vermont legalized same-sex marriage in 2009, it did not convert existing civil unions into marriages or require couples to choose. The legislature specifically clarified that “the civil marriage does not dissolve the civil union.”6Social Security Administration. POMS PR 02707.050 – Vermont A Vermont couple can technically hold both a civil union and a marriage to the same person at once. There is still no practical reason to do so, because the marriage already covers everything the civil union does.
You Cannot Marry a Different Person While a Civil Union Is Active
This is the detail that catches couples off guard. If you are in a civil union with one person, you generally cannot marry someone else without first dissolving that civil union. Vermont law permits a person in a civil union to marry the other party to that union, but not a third person.6Social Security Administration. POMS PR 02707.050 – Vermont Attempting a new marriage while an old civil union remains legally active creates serious complications.
Converting a Civil Union to Marriage
Conversion procedures vary, but the pattern is consistent: apply for a marriage license, have the marriage solemnized or file the paperwork required by the county, and the civil union either merges into the marriage or dissolves. Some states waive or reduce the license fee for a conversion. Once complete, you hold a single status with both state and federal recognition.
If your civil union was created in a state that later converted all civil unions to marriages automatically, you may already be legally married without having done anything. The county clerk’s office where the civil union was recorded can confirm your current status.
Keeping an unconverted civil union means leaving federal tax benefits, clearer Social Security eligibility, and employer plan protections on the table. The IRS, Department of Labor, and Social Security Administration all draw a firm line between marriage and civil unions for federal purposes.2Internal Revenue Service. Rev. Rul. 2013-17
If You Are Separating and Hold Both Statuses
Dissolving one status does not automatically end the other. Some same-sex couples who formed legal relationships before 2015 hold more than one: a civil union from one state and a marriage from another. If you divorce but never dissolve the civil union, that civil union may still be legally active, which affects future relationships, property rights, and benefits eligibility.
When you end a relationship, formally terminate every status that exists. Ending a civil union may require a court proceeding similar to a divorce, and jurisdiction gets complicated if you no longer live in the state where the civil union was created. A family law attorney familiar with that state’s rules is worth consulting, particularly when property or parental rights are in play.