A marathon filibuster by Missouri Senate Democrats entered its 39th hour on Wednesday morning.

A group of at least seven Democrats are blocking Senate Joint Resolution No. 39, a proposed constitutional amendment which supporters say would protect religious liberty. Opponents, on the other hand, argue that the bill would insert discrimination into the state constitution by giving new legal protections to opponents of marriage equality.

“This is a major scarring of equality in Missouri,” said Senator Maria Chappelle-Nadal, a leader of the filibuster. “We are living in an environment where hatred is alive, and we as a caucus are not going to tolerate it.”

The question could go before Missouri voters as soon as November if approved by the Republican-led House and Senate.

Voters in 2004 overwhelmingly (71%) approved a constitutional amendment that defines marriage as a heterosexual union.

Democratic presidential candidates Hillary Rodham Clinton and Bernie Sanders backed the filibuster.

“Marriage equality is the law. I stand with those filibustering in MO to make sure discrimination won't be,” Clinton messaged to her more than 5.64 million followers.

Sanders tweeted to his 1.63 million followers: “Standing up for our LGBTQ sisters and brothers is the duty of all elected officials. This should make us all proud.”

Dow Chemical was among the businesses lending their support for the Democratic effort. “Dow opposes Missouri Senate Bill #SJR39 and any efforts that allow for discrimination of any colleague or citizen,” the company tweeted.

The Human Rights Campaign (HRC), the nation's largest LGBT advocate, said that passage of the legislation would lead to LGBT people and their families being “at risk of being denied many basic services.”

“Taxpayer funded foster care providers and adoption agencies could refuse to place children in need of loving homes with same-sex couples. Taxpayer funded homeless shelters could turn away LGBT couples and their families,” the group said.

Senator Scott Sifton, a Democrat from St. Louis County, told The Los Angeles Times that the filibuster would continue.

“We're more than happy to keep going. This is a fight we're not going to back down from,” he said.