The U.S. Senate most likely will not vote on a bill that seeks to protect same-sex marriage until September.

According to Reuters, Democrats, who control the Senate, will first work on a $430 billion climate change and drug pricing bill announced last week.

The House approved the Respect for Marriage Act last month with the support of 47 Republicans. The bill was first introduced in 2009 by New York Representative Jerrold Nadler, a Democrat. Nadler said that it was important to codify the Supreme Court's marriage equality opinion in Obergefell after it struck down Roe v. Wade, which like Obergefell was based on the right to privacy.

The bill needs the support of 10 Republicans to clear the Senate. Five GOP senators have said they would vote for the measure.

The delay could cost votes, Reuters reported.

“Proponents of the bill worry that waiting could cause support to dwindle as opponents ramp up pressure on fellow Republicans to oppose it, according to a source familiar with the Senate negotiations,” the outlet wrote.

Axios reported that Democrats are considering some changes to the bill to increase Republican support.

Democratic Senator Tammy Baldwin, the Senate's first openly gay member, told Axios that backers are discussing providing “more clarity that the legislation would not take away any religious liberty or conscience protections.”

Changing or adding new language to the bill would require another vote in the House in an already crowded calendar.