It decides cases by applying Constitutional principles when considering oral arguments and written memoranda of law submitted by parties to an action and those who have submitted amicus briefs. Key to their decision is what standard of review to apply to laws banning same-sex marriage: whether rational basis, intermediate scrutiny or heightened scrutiny. These are bases upon which they justices will have decide whether the "good reason" that the government has to prevent same-sex couples from marrying is important enough to justify the impact such legislation has on gays and lesbians.
The Constitution
Washington, DC, which is the only city in the United States to have legalized same-sex marriage. The District of Columbia is the only city in the country that is part of any state. In the United States, marriage laws are controlled by the states, not cities. No city has the authority to pass laws concerning marriage. This is why some municipalities have passed local laws concerning domestic partnerships.
Same-sex marriage became an issue in the United States on May 18, 1970, when two men from Minnesota applied for a marriage license and were denied. They took their case to the Minnesota Supreme Court in 1971 and the the US Supreme Court in 1972.
The Supreme Courts of the United States, Canada and Mexico have all ruled that same-sex couples have a constitutional right to marry. Once same-sex marriage has been legalized in a jurisdiction, the law is identical for same-sex marriages as for opposite-sex marriages. Usually, each country has its own marriage laws. In the United States, Canada and Mexico, however, each state or province has its own marriage laws. Exact details of marriage laws vary from jurisdiction to jurisdiction.
Ones concerning the constitution, federal law, and 2 or more states, mostly
In the United States the US Supreme Court decides if laws meet the requirements of the US Constitution.
as of 2013, yes. But only by a majority of 5 to 4.
I assume you mean the United States Supreme Court. The U.S. Supreme Court has never issued a decision concerning same-sex marriage. In 1972, the Court dismissed Baker v. Nelson, 409 U.S. 810 (1972) for "want of a substantial federal question." The Plaintiffs had challenged Minnesota's denial of a marriage license on equal protection grounds. In January 2011, the U.S. Supreme Court refused to hear a challenge to the refusal of the Board of Elections of Washington DC to put a proposed initiative on the ballot which would define marriage as being between one man and one woman. The Board had refused to put the issue on the ballot citing DC's because it violates DC's Human Rights Law. Same-Sex marriage is legal in Washington, D.C.
In the United States, that power has always belonged to the legislatures of individual states. In 1996, however, the U.S. Congress enacted a law prohibiting the recognition of some marriages.
The people who live and work in the United States follow whatever laws concerning same-sex marriage apply to them in the state where they are located. People in other countries do the same.
There is no legitimate legal argument for limiting marriage to opposite-sex couples only. Denying same-sex couples the right to marry is a violation of the United States Constitution.
The Supreme Courts of the United States, Mexico and Canada have all ruled that same-sex couples have a constitutional right to marry. In those countries, a federal ban on same-sex marriage is no longer permissible, except that the state bans in Mexico must be struck down one at a time. The right of states to ban same-sex marriage is currently on appeal to the Brazilian Supreme Court, after a lower court ruled that states cannot ban it. In other countries, a countrywide ban on same-sex marriage is permissible because marriage laws are uniform nationwide.