WASHINGTON (AP) – Colorado Sen. Wayne Allard said he hopes this is the year the U.S. Senate will vote for his proposed constitutional ban on same-sex marriage, which cleared a key committee May 18 and is headed to the full Senate in June.

“Now is the time to send to the states a constitutional amendment that protects traditional marriage and prevents judges from rewriting traditional marriage laws,” said Allard, a Republican.

Allard and Rep. Marilyn Musgrave, R-Colo., sponsored the amendment in 2004, but it failed in both the House and Senate.

Last week’s party-line vote was a small victory. The Senate Judiciary Committee approved the measure, which states, “Marriage in the United States shall consist only of the union of a man and a woman.”

But its chances of passing the full Senate are slim. Democrats and opponents of the measure accused Republican leaders of pushing the amendment in an election year, purely for political reasons.

“Coloradans are embarrassed that Sen. Allard along with Rep. Musgrave are champions of enshrining discrimination in our nation’s most sacred document,” said Michael Brewer, a Denver gay rights advocate. “The effort to pass a federal marriage amendment is a political ploy to catalyze the most conservative members of the Republican Party.”

Allard said he sponsored the amendment to prevent judges from defining marriage without input from the majority of Americans.

“Truth is, the Constitution will be amended whether we pass this bill or not. The only question is whether it will be amended through the amendment process or by unelected, activist judges,” Allard said. “The constitutional amendment process allows the people a voice in the debate.”

The vote in the Senate is expected the week of June 5.

The contentious debate over the definition of marriage has raged not only in Congress but in the states. In Colorado, voters in November will decide whether to give same-sex couples some of the same rights as married couples under state law.

Efforts also are underway to allow voters to decide whether to ban same-sex marriage or to prohibit relationships similar to marriage.

A spokesperson for the Colorado Springs, Colo.-based Focus on the Family Action, a conservative Christian group, said marriage is “under attack” by the U.S. courts.

“It’s clear marriage needs to be protected, and we feel the only way to fully protect marriage is by a federal constitutional amendment,” said Amanda Banks, a Focus on the Family Action spokesperson.

Banks praised Allard and Musgrave for leading the effort in Congress. The upcoming vote will help voters know where their lawmakers stand on the issue when they go to the polls in November.

“It’s a good marker for values voters,” she said. “We’ll be ensuring our constituents … know how their senators and representatives voted on this issue.”

Brewer, the Denver gay rights activist, said he didn’t think conservatives would be successful in their ultimate goal.

“The American people are too fair-minded to allow for the first time this kind of discrimination to be amended into our Constitution,” he said.