A review of relevant U.S. laws and regulations has deepened questions about the marriage between the US Ambassador to a multilateral organization located in Austria and his same-sex partner over the weekend in Vienna.

Daniel Baer, U.S. Ambassador to the Organization for Security and Cooperation in Europe, tweeted the announcement; his friend Chad Griffin, president of the controversial gay rights group Human Rights Campaign, who was in attendance, also announced the ceremony.

The Ambassador made a statement to Advocate, a gay interest magazine, acknowledging such a wedding is not legal in Austria but saying it showed the Austrian government “what was possible.”

A review of US federal regulations about marriages overseas raises serious questions about whether the marriage as described was legally possible under US law.

First, same-sex marriage is not recognized by federal law in the United States. Marriage is the exclusive competence of the 50 states and the District of Columbia. Recent Supreme Court decisions and presidential orders deal almost exclusively with federal benefits available to same-sex couples who have been married in one of the various states that allow it and not with the legality of same-sex marriage itself.

As to US citizens marrying overseas – and the participation of Embassy and Consular officials and the use of official US property – it is explicitly not allowed under State Department regulations.

State Department guidance points out that host governments may require proof that the persons are free to marry. Since the US government cannot issue such a document, a notarized document is allowed but “must contain sufficient information to satisfy the local authorities.” One assumes the Ambassador was free to marry from his home state of Massachusetts, but it is unclear if his betrothed, environmental lawyer Brian Walsh, is also free to marry in his home state, which for now is unknown. Given that Austria does not allow same-sex marriage, such a document, if provided to them, would almost certainly have been rejected.

What about marriages, then, on Consular – that is US government – property in a foreign country? This is also not allowed.

The regulations state, “As a rule, marriages are not performed on the premises of an American embassy or consulate…” but this was where the Ambassador says his wedding ceremony was held. Moreover, according to international law, the private residence of the Ambassador is considered a part of US territory.

And who could have performed the ceremony? Pictures show the presider is a woman, but she is not identified. She could not have been a U.S. Consular official because regulations forbid it. The regulations state, “Marriages abroad are almost always performed by local (foreign) civil or religious officials,” except that would likely have been impossible since same-sex marriage is not legal in Austria.

Additionally, the regulations state, “The validity of marriages abroad is not dependent on the presence of an American diplomatic or consular officer but upon adherence to the laws of the country where the marriage is performed.”

So, the question remains, when Ambassador Baer announced he had married his partner in Austria over the weekend, exactly what did that mean?