House Democrats blocked a Republican-backed constitutional amendment that would have permanently limited the U.S. Supreme Court to nine justices.

The measure failed in a 212-206 vote, falling well short of the two-thirds majority required for a constitutional amendment.

Republicans argued the amendment was necessary to prevent Democrats from expanding the court if they regain control of Congress and the White House.

Democrats opposed the proposal as they seek to preserve the ability to pursue changes to the court, including possible expansion, amid its current conservative majority, NBC News has reported.

The vote comes ahead of the November midterm elections, making the size and future of the Supreme Court an increasingly important partisan issue.