Pivotal votes cast by U.S. Chief Justice John Roberts in abortion and death penalty cases have underscored his new standing as the Supreme Court's ideological center and the outsize role he may play in major rulings for years to come.

Roberts, a genial 64-year-old conservative appointed in 2005 by Republican President George W. Bush, sided with the nine-member court's four liberals on Thursday night in blocking a restrictive Louisiana abortion law from taking effect. He also sided on Thursday night with the four other conservative justices in allowing the execution of a Muslim convicted murderer in Alabama.

His vote in the abortion case was particularly noteworthy because it represented a turnaround from his vote in a 2016 abortion case in which he had joined two other conservatives in dissent when the Supreme Court ruled 5-3 to strike down similar regulations targeting abortion doctors in Texas.