A common law marriage is a marriage that is entered into informally, without a license. Informal marriages have been abolished in most states, but they are still available in a handful of states and the District of Columbia.

The required elements of common law marriage in DC are: (1) cohabitation; following (2) an express mutual agreement to be married, which must be in words of the present tense. In DC, unlike some other jurisdictions, there is no minimum duration of cohabitation required before the marriage is in effect. One misconception about common law marriage is that a cohabiting couple could inadvertently find themselves married after a given period of time, without ever having intended to enter into a marriage. This is not true; creating a common law marriage requires both cohabitation and an unambiguous statement of a present intent to be married. Living together, even for a long time, is not enough.

Marriage equality in DC has now extended the concept of common law marriage to same-sex couples. The cases establishing DC common law marriage are riddled with references to “husband and wife” and “man and woman,” but the Religious Freedom & Civil Marriage Equality Amendment Act of 2009 (the Marriage Equality Act) rendered neutral all the gender-specific language of the law relating to marriage.

There are no known statistics about how many marriages in force today were entered into informally. By their very nature, such marriages defy record-keeping. We usually become aware of an informal marriage only when:

• the relationship sours and one party seeks spousal support and division of assets;
• one party seeks to marry someone else (or does marry someone else, and is accused of bigamy); or
• one party has died and the survivor and/or their children seek to inherit or to receive other benefits dependent upon the marriage, such as Social Security, or the decedent’s estate claims the estate tax marital deduction for amounts left to the surviving “spouse.”

Imagine a same-sex couple, Robert and Jacob, who lived together in DC for decades. For most of that time, the law prevented them from marrying, but each considered the other to be his husband, and they agreed that they were married. They wrote sweetheart wills, leaving all of their assets to one another, and otherwise conducted their lives as though married. Eventually, DC law changed, making it possible for them to get married formally, but they never got around to it. Then Robert died, leaving his entire estate, worth $3 million, to Jacob.

In DC, there is a $1 million estate tax threshold. Assets of a DC-domiciled decedent that exceed this threshold are subject to DC estate tax unless they have been left to a surviving spouse, registered domestic partner, or charity. In this case, Jacob may be able to prove that he was Robert’s surviving common law spouse. If Jacob is successful, then Robert’s estate will not owe any DC estate tax.

If a legal impediment to marriage exists (e.g., one member of a couple is married to someone else), then the couple cannot become married at common law. When the impediment is removed (e.g., the prior marriage is dissolved), the common law marriage will become valid if the other requirements are met. For Robert and Jacob, when the Marriage Equality Act extended marriage to same-sex couples, the impediment to their informal marriage was removed.

Courts closely scrutinize claims of common law marriage, especially where one party is deceased and the survivor stands to gain financially. So Jacob will have to produce evidence of cohabitation (which should be easy enough) and their agreement to be married (which may be harder to prove). The best evidence of an express agreement to be married is the testimony of the parties. However, the validity of an informal marriage is usually tested only when one party is deceased (as in Jacob’s case) or is repudiating the marriage. Other evidence may allow a court to infer the existence of an agreement, such as the character and duration of cohabitation, witness testimony to the parties’ general reputation in the community as married, deeds to property, statements from jointly titled bank accounts, and jointly filed tax returns. In Jacob’s case, that he and Robert wrote sweetheart wills will be a helpful fact.

What if Robert’s estate had been $6 million? There is a federal estate tax imposed on estates that exceed the federal estate tax exemption (currently, $5.12 million, but scheduled to decline to $1 million on January 1 unless Congress acts). An unlimited federal marital deduction is available for assets left to a decedent’s surviving spouse. For opposite-sex couples, the IRS will recognize a marriage for tax purposes if valid under the laws of the state where the marriage was entered into (including valid common law marriages). However, the Defense of Marriage Act (DOMA) precludes the IRS from recognizing a same-sex marriage for federal tax purposes. Even if Jacob proves that he and Robert had a valid common law marriage under DC law, if DOMA stands, he will not receive the benefit of the federal estate tax marital deduction. The constitutionality of DOMA has been hotly contested. On May 31, 2012, in Massachusetts v. U.S. Dept. of Health and Human Services, the 1st Circuit U.S. Court of Appeals in Boston held that DOMA is unconstitutional insofar as it denies federal benefits to same-sex couples legally married in a jurisdiction that permits same-sex marriage.

Common law marriage is not available in Virginia or Maryland. Maryland will recognize a common law marriage if validly entered into in a jurisdiction, such as DC, that permits such marriages. The law of Maryland regarding recognition of same-sex marriage is still developing. In May, 2012, in Port v. Cowan, the Maryland Court of Appeals held that Maryland law recognizes a same-sex marriage valid where celebrated for purposes of allowing a same-sex couple to get divorced in Maryland.