Texas lawmakers are gearing up to pass one of the country’s most aggressively anti-same-sex-marriage bills this week. The bill, HB 4105, would prohibit state and local governments from recognizing, granting or enforcing same-sex marriage licenses. More than half of the members of Texas’ House of Representatives have signed on as co-sponsors to the bill, making its passage in that chamber likely before the Thursday deadline the House has for House bills to be heard on the House floor.

The measure’s sponsors say it is a pre-emptive move ahead of a U.S. Supreme Court ruling expected in June that could legalize same-sex marriage nationwide.

“We as Texans have a sovereign right to define and regulate marriage,” Republican state Rep. Cecil Bell, the author of the bill, told TPM on Tuesday. “I don’t believe that this bill puts anyone in a lesser position than what they were in before. What this does is codify Texas law.”

As gay marriage headed to the U.S.’s highest court, state legislators across the country introduced measures to undercut efforts to expand marriage rights to same-sex couples. Texas lawmakers put forward some 20 anti-gay bills this term.

Bell’s bill and another measure that guarantees that clergy would not have to participate in marriages that violate their faith are the only Texas bills to make it out of committee. The clergy bill has been narrowed in scope during the amendment process to the point that Democrats and LGBT rights activists are comfortable with it.

Supporters say they have a similar level of support for HB 4105 in the state Senate as they do in the state House. Gov. Greg Abbott (R) has not yet taken a public stance on the measure. If passed, both measures will likely not go into effect until September, and HB 4105’s constitutionality could be challenged, depending on how the Supreme Court rules on same-sex marriage in Obergefell v. Hodges, where a decision is expected in late June.

“It’s going to cause confusion and unnecessary litigation,” says Eric Lesh, Fair Courts Project Manager for Lambda Legal, which opposes HB 4105.

There are also concerns about a backlash to the measure, with Texas business leaders warning Texas legislators that anti-gay measures are bad for the state’s economy. Indiana faced boycotts when Republican Gov. Mike Pence signed a so-called religious freedom law in March that could have given businesses the right to discriminate against gay couples; lawmakers there rushed to amend the bill to clarify that it could not be used to discriminate against same-sex couples.

“Astonishingly, some Texas lawmakers seem to have completely missed—or are purposely ignoring—the lessons learned from the harmful anti-LGBT debacle in Indiana,” said Stephen Peters, a Human Rights Campaign spokesman, in a statement. “These bills have nothing to do with Texas values and have everything to do with enshrining discrimination into state law.”

Correction: This story previously said the Texas legislative session concluded Thursday. The regular legislative session concludes in June. Thursday is the deadline for House bills to be heard on the House floor.