(Bloomberg) -- Chief Justice John Roberts, known for trying to bridge ideological divides on the Supreme Court, failed to persuade his conservative counterparts to stop short of stripping away a woman’s right to an abortion. 

Roberts alone said he would have upheld Mississippi’s 15-week abortion ban without overturning Roe v. Wade, the 1973 decision that legalized abortion nationwide. He said he would have waited to decide whether tighter restrictions on abortion were constitutional.

“I am not sure, for example, that a ban on terminating a pregnancy from the moment of conception must be treated the same under the Constitution as a ban after fifteen weeks,” Robert said in a separate opinion.

Roberts wrote that he “would take a more measured course” than the majority. Rather, he would eliminate a standard set by Roe and another past ruling, Planned Parenthood v. Casey, that gave women the right to an abortion up to the point a fetus can live outside of the womb. 

Roberts called the court’s majority opinion Friday to overturn the past precedents a “serious jolt to the legal system.” He urged “judicial restraint.”

“If it is not necessary to decide more to dispose of a case, then it is necessary not to decide more,” Roberts said.

He sided with the majority in his disdain for the viability standard set by Roe arguing that the US stood apart in its loose restrictions on abortion. He said only a handful of countries -- he cited China and North Korea -- permit abortions after 20 weeks.

“There is a clear path to deciding this case correctly without overruling Roe all the way down to the studs: recognize that the viability line must be discarded, as the majority rightly does, and leave for another day whether to reject any right to an abortion at all,” he wrote, in offering his fellow justices another path.

But no other justices joined him.

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