Chief Justice John Roberts joined the court's liberal bloc in a 5-4 decision that halted the law, which would have required abortion doctors to obtain admitting privileges at hospitals within 30 miles of a clinic.
President Donald Trump's two Supreme Court appointees, Justices Neil Gorsuch and Brett Kavanaugh, were among the four conservative members of the court who would have allowed the law to take effect. He is, by most measures, a very conservative justice, but he seems determined to keep the court from moving too far right too fast and being perceived as just another forum for partisan politics in Washington.
As a result of Thursday's order, Act 620 will remain blocked while the Court considers taking the case on the merits. Backers of these bills said they were undeterred by the Supreme Court's latest action. But unless and until it does, the future of abortion rights is still in legal jeopardy.
Since the retirement of Justice Anthony Kennedy last summer, Roberts has become the court's new swing vote. Which means he will nearly certainly vote to uphold the Louisiana law once the court hears it in full.
"The U.S. Court of Appeals for the 5th Circuit maintained that the burdens imposed by Louisiana's admitting privileges requirement are less severe than the burdens imposed by the same requirement in Texas", writes Litman.
Former Vermont Gov. Howard Dean, who served as the national Democratic Party chairman after losing a 2004 bid for president, said on Twitter that Collins will have to defend her vote for Kavanaugh next year if she runs for re-election "because it's likely Roe will not exist" any longer.
So on issues like that one, Roberts will tread carefully, trying to accomplish conservative goals while protecting the Republican Party from the consequences of its worst instincts. It will be the Roberts Court that does it, after oral arguments and deliberation.
Translation: The Fifth Circuit majority threw the rule of law and proper appeals court procedure out the window.
Michaelson proposes an analogy in which a law is passed that requires doctors who perform abortions to "wear polka dotted shirts with striped ties and clown shoes", and argues that by Kavanaugh's logic, if the doctors could obtain the clothes, this would not constitute an "undue burden".
Now, that Louisiana law may be heading to the Supreme Court.
It's also possible that at some later date the Court could reaffirm, yet again, its support for Roe and overturn the Louisiana law or similar TRAP laws adopted by other states.
The one conservative who did not vote to ignore SCOTUS precedent is the only conservative on the court who you could say cares more about the legitimacy of the Supreme Court than conservative ideology.
Has Roberts "committed himself to reaffirming Whole Woman's Health or any of the court's other abortion decisions?" There's no guarantee that Roberts will be with his liberal colleagues then.
Hogue told me, "Susan Collins gaslighted millions of Americans claiming we were hysterical in believing that Justice Kavanaugh would vote to overturn precedent".
There are few high-profile cases on the court's docket this year, seemingly by design, after Kavanaugh's tumultuous confirmation hearings.
"We're elated - but not in the sense of uncorking the champagne", said Center for Reproductive Rights attorney Travis Tu, who has helped lead the fight against the Louisiana law. He created for the first time an individual right to own guns in District of Columbia v. Heller.
The action, which four justices opposed, followed by less than two months the Supreme Court's refusal to review lower court opinions rejecting decisions by Kansas and Louisiana to remove Planned Parenthood as a Medicaid provider.