CHICAGO (Reuters) - A 39-hour Democratic filibuster in the Missouri Senate ended on Wednesday when Republicans forced a vote and approved a proposal to prohibit sanctions against groups and wedding vendors that discriminate against same-sex couples for religious reasons.

The resolution to amend the state’s constitution passed 23-9 after the majority Republican caucus used a parliamentary maneuver to end the filibuster, which began at 4:00 p.m. CST on Monday, said Lauren Hieger, communications director for the Missouri Senate Majority Caucus.

The amendment must be voted on again in the Senate next week before passing to the lower house, where Republicans have a majority, and then to the state’s voters, Hieger said.

Missouri Governor Jay Nixon, a Democrat, applauded the effort by the Senate minority to block the resolution. “Rewriting our state’s constitution to condone discrimination would be contrary to our values and harmful to our economy,” Nixon said in a statement on Wednesday.

The legislation is among a series of measures introduced around the country by conservatives in response to last year’s U.S. Supreme Court legalization of same-sex marriage. The measures seek to protect religious groups and companies from being fined or punished if they decline to provide services such as wedding cakes or flowers to same-sex couples.

Republicans who backed the amendment said it was about religious freedom, but Democrats said it would enshrine discrimination in the state’s constitution.

Given their minority position in both chambers of Missouri’s General Assembly, Democrats chose to filibuster, debating overnight on Monday and Tuesday to block the initiative.

“Inspired by senators’ heroic stand against discrimination in #MO. The nation is watching & cheering you on!” Nixon tweeted on Tuesday night.

“In our pluralistic society, we should have room to respect the religious freedom of Missourians,” Republican Senator Bob Onder, who sponsored the bill, told reporters at a news conference on Wednesday morning. He said the language of the bill was modified in a compromise on Tuesday to narrowly define wedding vendors.

The American Civil Liberties Union civil rights group said it would work to fight the bill in Missouri’s House of Representatives.

“This amendment raises serious constitutional concerns because it singles out same-sex couples for discrimination,” Jeffrey Mittman, executive director of ACLU of Missouri, said in a statement.