The Senate Republican leadership is aiming for a mid-July vote on a constitutional amendment that would ban gay marriage, forcing Democrats to take a stand on the controversial topic just before the party heads to Boston for its presidential nominating convention.

Republican Conference Chairman Rick Santorum (Pa.) said the GOP leaders are not yet prepared to make an official announcement on a specific date, but confirmed that they are scouting for a July vote.

“We are sort of running the traps on this right now, and sort of seeing what kind of response we are getting,” Santorum said following Tuesday’s Republican policy lunch. “We are talking about it. I think there are a couple of meetings to be had yet before any official announcement is made.”

The issue was not discussed with all 51 Republican Senators at the Tuesday meeting, but a handful of senior Senators and leaders “discussed the issue at length” Monday night, several GOP Senators and aides said. There was not unanimity in that chairmen’s meeting about whether the GOP should pursue the issue in this election year, but there appears to be a strong majority within the Republican Conference to at least force a vote.

“I think it needs to come up and we need to vote on it one way or another,” said Judiciary Chairman Orrin Hatch (R-Utah).

Conservative pro-family groups have been pressuring the Republican-controlled Congress to hold a vote on the issue this year, sparked in part by Massachusetts’ decision in May to sanction gay marriages. Some Republicans hope the decision to move the vote up to July would help inoculate the GOP from Democratic charges that the party is trying to play politics with an issue right before an election.

“We want to make sure we are as clear as possible that this is not a political exercise but an issue of substance,” said a GOP aide, who spoke on the condition of anonymity.