PHOENIX — Foes of gay marriage won a crucial victory Tuesday in the House.

 Without comment, lawmakers gave preliminary approval to a measure to constitutionally define marriage as solely between one man and one woman.

 That language had been approved earlier this month on a different bill. But that occurred only after it was amended to also grant certain rights to unmarried couples.

 The additional provision was unacceptable to those who oppose same-sex marriages. So they let that bill die, with the plan of resurrecting the measure again.

 This time, though, Rep. Kyrsten Sinema, D-Phoenix, did not offer that same amendment. Cathi Herrod, president of the Center for Arizona Policy, said her group had lobbied to find enough votes to kill it.

 A final House roll-call vote scheduled for later today will send SCR 1042 to the Senate, which has not yet debated the issue this session.

 The procedure used by supporters of the new version of the gay marriage ban effectively precludes opponents from trying to amend the measure in the Senate.

 That’s because the verbiage is attached to an unrelated bill which already has been approved by the Senate. That means senators have only two choices: approve the House-passed version of the measure or reject it, with no opportunity to amend it.

 Sinema was testy with reporters who questioned what plans — if any — she has to derail the measure. “Do you think I’m going to answer that question?’’ she said. “Do I look stupid?’’ Sinema said responding to queries would be the equivalent of giving away her strategy. “And if I have one, which I may, I’m not telling you guys,’’ she said.

 But Rep. Eddie Farnsworth, R-Gilbert, who is pushing the ban, said he sees Tuesday’s action — and Sinema’s failure to again try to amend the bill — as an important signal. “She obviously didn’t have the votes,’’ he said.

 Tuesday’s action is an important move to putting the issue on the ballot in November.

 Voters narrowly rejected a similar measure in 2006. That proposal, however, would have done more than ban same-sex marriages. It also would have barred the courts or lawmakers from recognizing “civil unions’’ that would grant some of the same privileges as marriage and prohibited governments from providing benefits to the domestic partners of their employees. Farnsworth said he believes voters would approve a simple ban on gay nuptials.

 Several polls have suggested he is correct. They found fairly wide support for limiting marriage to one man and one woman but deeper division — and sometimes outright opposition — to questions of civil unions and insurance benefits.

 Herrod said Tuesday she is working to ensure there are enough votes in the Senate to put the measure on the ballot.