The Indiana Senate is expected to vote as early as Wednesday on a resolution that aims to ban gay marriage in the state.

Last week, the proposed constitutional amendment won the approval of the Senate Judiciary Committee. The House overwhelmingly approved the measure with a 70-26 vote late last month. The Senate has approved a similar measure in the past and the bill is expected to face little opposition in the Republican-controlled chamber.

Voters, however, won't vote on the proposal to alter the state constitution until 2014 at the earliest, after a separately-elected General Assembly approves the resolution. If approved by voters, the amendment would also ban civil unions and possibly domestic partnerships.

Supporters of the bill, sponsored by Representative Eric Turner, a Cicero Republican, testified last week in committee that the amendment was needed because the state's gay marriage ban remains vulnerable to a legal challenge. Indiana courts, however, have already declared the state's 1997 law constitutional.

“Two-thirds of the states have amended their constitutions because of the legal challenges that have occurred,” Micah Clark of the American Family Association of Indiana said. “For example, Iowa had a law similar to ours [and then] had same-sex marriages forced on them by the courts.”

Marriage equality supporters held a rally at the Statehouse last Monday.