If the Senate passes the bill with the bipartisan amendment, the amended version would return to the House for another vote before it could go to Biden to sign into law. The timing of the Senate vote was uncertain though lawmakers could vote as early as Thursday.

In his June concurrence with the decision to overturn Roe, Supreme Court Justice Clarence Thomas wrote that the high court should also examine previous rulings that legalized the right of married couples to buy and use contraception without government restriction (Griswold v. Connecticut), same-sex relationships (Lawrence v. Texas) and marriage equality (Obergefell v. Hodges).

“In future cases, we should reconsider all of this Court’s substantive due process precedents, including Griswold, Lawrence, and Obergefell,” Thomas wrote. “Because any substantive due process decision is ‘demonstrably erroneous’ … we have a duty to ‘correct the error’ established in those precedents.”

“After overruling these demonstrably erroneous decisions, the question would remain whether other constitutional provisions guarantee the myriad rights that our substantive due process cases have generated,” he added.

Thomas’s opinion set off alarm bells among proponents of marriage equality, particularly with the prospect of a Republican-controlled Congress after the midterm elections. However, Republicans drastically underperformed expectations last Tuesday, and Democrats will retain their majority in the Senate. A Dec. 6 runoff in Georgia - between Sen. Raphael G. Warnock (D) and Republican Herschel Walker - will determine whether Democrats gain a 51st Senate seat.

Republicans are expected to win a narrow majority in the House, though several races remain undecided.

Liz Goodwin contributed to this report.

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