It has been no secret that supporters of abortion rights have been on the defensive for the last two decades as opponents passed one legislative action after another in Republican controlled states that limited the availability of abortion services to women. These took the form of long waiting periods, requiring multiple visits to clinics, forcing younger women to notify their parents and the fathers, forcing doctors to issue scary warnings to women about the dangers of abortions and forcing women to listen to them, and so on. The goal seemed to be that if they could not ban abortions entirely, they could make it so hard to get that the right was almost nullified.

As Nina Martin of ProPublica writes, the case that made a mess of the right to abortion that was granted in the famous 1973 case Roe v. Wade and opened the window that made this strategy viable was the 1992 Planned Parenthood of Southeastern Pa. v. Casey that challenged a Pennsylvania law that required “a 24-hour waiting period, informed consent rules for women seeking abortions, parental consent rules for minors, and a requirement that married women notify their husbands before terminating a pregnancy.”

All but the last requirement was upheld by the Third Circuit Court of Appeals and the case went to the US Supreme Court that was then at the height of its conservative power with eight Republican appointees in chief justice Rehnquist and justices Scalia, Thomas, O’Connor, Stevens, Souter, Kennedy, and Blackmun and the only Democratic appointee being White who was also pretty conservative, especially in his later years. There were fears that the court might use the Casey case to actually overturn Roe. While Blackmun (the author of the Roe opinion) and Stevens would likely not support overturning it, they seemed to be the only two sure votes. Opponents of abortion were hopeful that they could get at least one of the so-called moderates (O’Connor, Souter, and Kennedy) to join with hardcore opponents Rehnquist, Scalia, Thomas, and White (who had dissented from Blackmun’s opinion in Roe) to not only uphold the Casey restrictions but overturn Roe itself.

As Martin says, from Blackmun’s papers we learn that at one point that majority seemed to be there and Rehnquist was drafting a 5-4 majority opinion that would effectively overturn Roe.

But then the trio of Republican-appointed moderates— Anthony Kennedy, Sandra Day O’Connor, and David Souter—had second thoughts. Instead of joining Rehnquist, they made a secret deal to thwart him.

The Planned Parenthood of Southeastern Pa. v. Casey decision, announced in June 1992, was stunning. By a 5-4 vote, the court reaffirmed Roe’s “essential holding” that the right to abortion was protected by the Constitution. Not only that, the opinion embraced women’s equality as central to the abortion right in a way that Roe had not.

(You can read the opinions here.)

But the compromise that saved abortion as a fundamental right also opened the door to the strategy of chipping away at access.

More significantly, Casey also rejected Roe’s “strict scrutiny” test for evaluating abortion restrictions—a test that had stymied most state efforts to regulate the procedure—replacing it with the looser “undue burden” standard, which Justice O’Connor had proposed in dissents to earlier abortion rulings. An undue burden was defined as any law that had “the purpose or effect of placing a substantial obstacle in the path of a woman seeking an abortion.” Importantly for the pending Texas abortion case, this reasoning applied to medical rules as well as other restrictions: Although “the State may enact regulations to further the health or safety of a woman seeking an abortion,” the court held, “unnecessary health regulations that have the purpose or effect of presenting a substantial obstacle to a woman seeking an abortion impose an undue burden.” Still, the court reiterated, just because a law had “the incidental effect of making it more difficult or more expensive to procure an abortion” wasn’t enough to invalidate it.

It was this vague ‘undue burden’ standard that was being exploited time and again to steadily impose restrictions by using arguments that made it “more difficult or more expensive to procure an abortion” while using the guise of other concerns so as to make these restrictions seem like “incidental” consequences of the laws. The biggest threats were those like in Texas that imposed such onerous conditions on clinics that many were forced to shut down and many of the remaining ones were threatened too. That would result in women being forced to travel long distances, creating substantial burdens on them.

It was this threat that was overturned by the US Supreme Court on Monday and it might be a sign that abortion opponents had pushed their struggle too far because the opinion, in clarifying the ‘undue burden’ standard, opened the door to a possible rollback of restrictive measures. In writing the majority opinion, justice Breyer compared the benefits that the methods were supposed to provide women with the costs and risks and with what was required for other procedures and concluded that “[N]either of these provisions offers medical benefits sufficient to justify the burdens upon access that each imposes.”

This does not mean that similar measures passed in other states automatically become non-operative. But it does mean that when lawsuits are brought against them, the courts will have to use these new guidelines to judge their validity and there is a good chance that they will also be struck down.

Stephanie Toti, the attorney who led the challenge to the Texas law, called the ruling “sweeping” and “decisive” for how it clarifies and strengthens the two-decade-old undue burden standard (which ProPublica wrote about here). Breyer’s reasoning “applies to all abortion restrictions across the board,” she said, and will be used to challenge other types of abortion laws that have recently gained momentum.

As a sign of things to come, the Supreme Court on Tuesday let stand two lower court decisions that had blocked measures in Mississippi and Wisconsin that were similar to those in Texas. This article provides a review of what the recent decision implies.

By striking down Texas’s tough abortion restrictions, the Supreme Court “has emboldened abortion-rights activists nationwide and imperiled a range of anti-abortion laws in numerous states,” the conservative site NewsMax reported, adding that anti-abortion leaders were “bracing for the demise of restrictions that they had worked vigorously to enact over the past few years.” Clarke Forsythe, senior counsel at Americans United for Life, told Bloomberg that his group doesn’t read the decision ”as foreclosing all clinic regulations and admitting privilege requirements, but it clearly puts a greater burden on the states to give the justices more evidence.” The Supreme Court’s decision only applies to Texas, Vox’s Sarah Kliff and Sarah Frostenson point out. “Each of the other state laws will need to be challenged and also found unconstitutional.”

The battle over abortion is by no means over. Like with intelligent design advocates, opponents will try to find new ways of advancing their cause. Look for new arguments that will seek to use the onset of ‘fetal pain’ as the new yardstick for measuring the point at which abortion should be prohibited.

What is significant about this decision is that there has been a shift away from supporters of abortion rights fighting to safeguard the fundamental right to abortion while losing battles that whittled away at it, to now going on the offensive and trying to regain past lost ground.