A divided U.S. Supreme Court on Thursday stopped a Louisiana law imposing strict regulations on abortion clinics from going into effect in its first major test on abortion since the retirement of Justice Anthony Kennedy last summer.

The court on a 5-4 vote granted an emergency application by Shreveport-based abortion provider Hope Medical Group for Women to block the Republican-backed law from going into effect while litigation continues.

The four liberal justices were joined by conservative Chief Justice John Roberts in the majority, suggesting that Roberts, as Kennedy used to be, is now the key vote on the issue.