When a split Arizona Supreme Court upheld a Civil War-era abortion ban this week, it rejected the argument that the 160-year-old statute had been overtaken by decades of newer laws regulating the procedure, including a recent law banning abortion after the 15th week of pregnancy.

But to better understand the court itself, look no further than the year 2016, when Gov. Doug Ducey, a Republican, successfully expanded the court’s membership from five to seven justices.

By the time Mr. Ducey left office at the end of 2022, he had easily eclipsed the state record for judicial appointments to various courts. He had also changed the nominating process by which judges are selected, essentially giving more power to the governor.

And as an ardent conservative who frequently railed against big government and championed restrictions on immigration, he also shaped an all-Republican State Supreme Court into one that had an even more libertarian, prosecutorial and conservative activist bent.

As a result, all four of the justices who were part of the majority decision in the abortion case on Tuesday were appointed by Mr. Ducey, while the two justices who dissented over any attempt to revive the earlier law were appointed by Mr. Ducey’s Republican predecessor, Jan Brewer.

Mr. Ducey’s imprint might have been even more pronounced, had one of his appointees, Justice William G. Montgomery, not recused himself in response to complaints about a 2017 Facebook post in which he said that Planned Parenthood, one of the parties in the case, was “responsible for the greatest generational genocide known to man.”