Key moments in the history of same-sex marriage

1972 — Minnesotan Jack Baker files a lawsuit after being denied a marriage license for his male partner. The suit is thought to be the first same-sex marriage lawsuit in the U.S.

October 1972 — Minnesota Supreme Court rejects an appeal of Jack Baker's suit regarding the denial of his marriage license to his male partner.

1974 — Minnesota Sen. Allan Spear, DFL-Minneapolis, announces he is gay, becoming the state first openly gay male legislator and one of the first in the country.

1997 — Minnesota defines marriage as "a civil contract between a man and a woman"

1984 — Minnesota Supreme Court expands the criminal ban on sodomy.

1991 — Minneapolis enacts the state's first domestic partnership ordinance. It would be 19 years before another city followed suit: Duluth, in 2009.

1993 — Through law and directive the "Don't Ask, Don't Tell" policy governs the military, banning military officials from asking applicants about sexual orientation.

April 1993 — Minnesota expands the Human Rights Act, outlawing discrimination based on sexual identity and including gays and lesbians in the classes protected against hate crimes. The measure passed on a bipartisan basis and was signed by Republican Gov. Arne Carlson.

September 1996 — The federal Defense of Marriage Act is signed into law. The Act states, "the word 'marriage'

means only a legal union between one man and one woman as husband and wife, and the word 'spouse' refers only to a person of the opposite sex who is a husband or a wife."

May 1997 — Minnesota adopts the state's Defense of Marriage Act. The Act prohibits, "a marriage between persons of the same sex" and says "a marriage entered into by persons of the same sex, either under common law or statute, that is recognized by another state or foreign jurisdiction is void in this state and contractual rights granted by virtue of the marriage or its termination are unenforceable in this state."

November 1998 — Alaska voters constitutionally ban same-sex marriage and Hawaii voters say that defining marriage is only the purview of lawmakers.

April 2000 — Vermont legalizes civil unions between gay couples, the first state with such a law.

November 2000 — Nebraska voters constitutionally ban same-sex marriage.

November 2002 — Nevada voters constitutionally ban same-sex marriage.

June 2003 — U.S. Supreme Court rules that sodomy laws in the U.S. are unconstitutional.

November 2003 — Massachusetts Supreme Judicial Court rules that barring same-sex marriage is unconstitutional.

2004 — 2006 — Minnesota lawmakers consider but do not pass a constitutional ballot measure defining marriage as only the union of a man and a woman. Then-state Sen. Michele Bachmann, a Republican, is among the leaders of the move toward constitutional definition.

May 2004 — Massachusetts legalizes same-sex marriage.

April and November 2005 — Kansas and Texas voters ban same-sex marriage.

October 2006 — New Jersey Supreme Court rules against ban on same sex marriage.

June — November 2006 — Alabama, Idaho, Colorado, South Dakota, South Carolina, Tennessee, Virginia and Wisconsin voters constitutionally ban same-sex marriage.

May 2008 — California Supreme Court rules same sex marriage should be legal. Marriage licenses are issued the next month, then banned again in a voter proposition. After a series of court rulings, the U.S. Supreme Court will likely decide this June on whether same sex marriage can or cannot be banned.

October 2008 — Connecticut Supreme Court rules banning same-sex marriage is unconstitutional and that state begins issuing marriage licenses to same sex couples.

April 2009 — Iowa Supreme Court rules banning same-sex marriage is unconstitutional and same sex marriages becomes legalized in that state.

April 2009 — Vermont Legislature legalizes same-sex marriage, over a governor's veto.

June 2009 — New Hampshire legalizes same-sex marriage.

December 2010 — President Obama says his feelings about same-sex marriage are "evolving."

May 2010 — Three Minnesota same-sex couples file suit arguing that the ban on same-sex marriage violates their rights.

July 2010 — Target Corporation finds itself at the center of a national uproar and boycott after it contributions to a political group helping Republican gubernatorial candidate Tom Emmer, who opposed same sex marriage.

December 2010 — President Obama signs a law allowing gay military members to service openly, ending "Don't Ask, Don't Tell."

March 2011 — A Hennepin County judge dismisses the lawsuit from three same-sex couples that sought to challenge the state's ban on gay marriage. Later, after appeals, the suit is put on hold until June 1, 2013.

May 2011 — President Obama says he supports same-sex marriage.

May 2011 — Firebrand pastor Bradlee Dean, who has spoken admiringly of a time when homosexuality was illegal, is guest pastor in the Minnesota House.

May 2011 — The Minnesota Legislature puts a constitutional amendment on the 2012 ballot that would define marriage as only the union of one man and one woman.

September 2012 — Democrats approve a same-sex marriage plank in their national party platform.

November 2012 — Washington state voters approve same-sex marriage in that state.

November 2012 — Maine voters approve same sex marriage in that state.

November 2012 — Minnesota becomes the first state to reject a constitutional amendment to ban same-sex marriage. The measure garners 47 percent yes votes.

May 2012 — Rhode Island passes a law legalizing same sex marriage.

2013 — A series of U.S. Senators, including some Republicans, say they support same-sex marriage.

March 2013 — U.S. Supreme Court hears oral arguments on cases that could determine whether banning same-sex marriage is permissible or whether legalization is required.

May 13, 2013 — The Minnesota Senate voted 37-30 to legalize same-sex marriage. Gov. Mark Dayton is expected to sign the measure into law on May 14, making Minnesota the 12th state to legalize same-sex marriage.

Summer 2013 — The U.S. Supreme Court expected to rule on same-sex marriage legalization.