The U.S. Supreme Court on Monday struck down a pair of strict Texas abortion regulations, sparing nearly a dozen clinics in the state from imminent closure and deflating a years-long effort by conservative lawmakers around the country to limit the procedure.

The ruling, the nation's most significant clarification of abortion law in a generation, was 5-3, with conservative Justice Anthony Kennedy siding with the court's four liberals against the regulations, which required abortion doctors to obtain admitting privileges at a nearby hospital and clinics to comply with the expensive standards of ambulatory surgical centers.

Those regulations, the majority found, were medically unnecessary and too strict for too many abortion providers to meet, forcing closures and thus making it unconstitutionally difficult for women to access the procedure.

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"We conclude that neither of these provisions offers medical benefits sufficient to justify the burdens upon access that each imposes," Justice Stephen Breyer wrote in the majority's opinion. "Each places a substantial obstacle in the path of women seeking a previability abortion, each constitutes an undue burden on abortion access, and each violates the Federal Constitution."

"In the face of no threat to women's health," Breyer added, "Texas seeks to force women to travel long distances to get abortions in crammed-to-capacity superfacilities."

Chief Justice John Roberts and Justice Samuel Alito objected to the ruling on largely technical grounds, leaving Justice Clarence Thomas as the most passionate defender of the regulations.

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The larger-than-expected victory for abortion rights is expected to reverberate around the country for years to come, especially due to new precedents that seemed to establish the safety of abortion and the need for courts to closely scrutinize legislative claims about the necessity of regulations to protect women's health.

Most immediately, similar laws in nearly a dozen other states are likely to be affected by the ruling, making abortion easier to access for tens of millions of women nationwide.

"Today women across the nation have had their constitutional rights vindicated," said Nancy Northup, president and CEO of the Center for Reproductive Rights, a New York-based organization that ran the legal challenge to the regulations. "The Supreme Court sent a loud and clear message that politicians cannot use deceptive means to shut down abortion clinics."

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Texas state officials decried the ruling, saying that an activist court had usurped the power of lawmakers and endangered women.

"The decision erodes States' lawmaking authority to safeguard the health and safety of women and subjects more innocent life to being lost," Gov. Greg Abbott said in a statement. "Texas' goal is to protect innocent life, while ensuring the highest health and safety standards for women."

Lt. Gov. Dan Patrick said the Texas Senate would revisit the issue, adding that lawmakers would have to review the ruling to determine their options.

"The Supreme Court appears to think it is the medical board for the entire country," he said. "What they ruled should be troubling to every citizen."

The decision caps more than three years of drama over the regulations, which were part of an omnibus anti-abortion bill that was thrust into the national spotlight when it was filibustered by then-Democratic state Sen. Wendy Davis in June 2013. The omnibus bill, which at the time was considered the most far-reaching abortion law in the country, was slowed but eventually passed as House Bill 2 and signed by then-Gov. Rick Perry.

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On Monday, Davis, who lost a bid for governor after the filibuster, told MSNBC that she was "overjoyed" by the ruling and fought back tears while reading it.

"It's incredible news for the women of Texas and the women of the country," she said, predicting it will take several months "to see us rebound to a place where women throughout the state have the access they once had" to abortion clinics.

House Bill 2 also banned almost all abortions after 20 weeks of pregnancy and limited the use of the so-called abortion pill. Those provisions were not challenged and remain in place.

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The regulations drew the fiercest criticism, sparking two separate challenges by abortion providers. An Austin-based federal judge struck down the law twice, but both decisions were overturned by the News Orleans-based 5th U.S. Circuit Court of Appeals. The Supreme Court initially declined to hear the case but later agreed – and twice stepped in to put parts of the law on hold.

While the case made its way through the legal system, the reality of abortion in Texas changed dramatically. More than half of the 41 abortion clinics in operation before the law's passage already have shuttered, mostly due to the admitting privileges mandate, while wait times have risen and the number of abortions has dropped.

Allowing the law to fully take effect had been expected to leave fewer than 10 abortion facilities to serve a state of 27 million people. All would be in major cities: San Antonio would have had three facilities, while Houston and Dallas would have had two and Fort Worth and Austin would have had one.

Read the full ruling below.

Abortion providers argued that would have constituted a "substantial obstacle" to accessing the procedure, which was the limit set by the Supreme Court's last major abortion case, Planned Parenthood v. Casey, which was decided in 1992.

The providers were joined in the case by the Obama administration.

On Monday, Obama released a statement saying he was "pleased" with the Supreme Court ruling.

Texas officials had argued that the regulations protected women's health and did not constitute a substantial obstacle, in part, they said, because abortion providers could comply if they wanted.

The chances of victory for the state dropped with the death of Justice Antonin Scalia, a fierce abortion opponent who died just before the oral arguments in Washington, D.C., in early March. Still, supporters of the rules had hoped Kennedy would side with the three remaining conservatives to force a tie, which would have left in place the 5th Circuit's ruling in favor of the regulations.

Instead, Kennedy joined with the liberals in the sweeping ruling, which agreed with the providers about the burden of the regulations on clinics but focused much of its attention on the safety of the procedure.

Breyer, who was appointed to the court by former President Bill Clinton, wrote extensively about the safety of abortion. He added that, "when directly asked at oral argument whether Texas knew of a single instance in which the new requirement would have helped even one woman obtain better treatment, Texas admitted that there was no evidence in the record of such a case."

Justice Ruth Bader Ginsburg wrote a concurring opinion focused on the health issue, concluding that "it is beyond rational belief that H.B. 2 could genuinely protect the health of women."

In his dissent, Thomas said the majority ruling "exemplifies the Court's troubling tendency 'to bend the rules when any effort to limit abortion, or even to speak in opposition to abortion, is at issue.'"

He also argued that the majority had misconstrued the court's precedent from Casey in an attempt to expand the right to an abortion.

Roberts and Alito focused on arguing the technical point that the challenge should not have been allowed because an earlier challenge to the regulations had already failed.

"Determined to strike down two provisions of a new Texas abortion statute in all of their applications, the Court simply disregards basic rules that apply in all other case," the conservative justices wrote.

The majority opinion rejected that argument, saying, "Imagine a group of prisoners who claim that they are being forced to drink contaminated water. These prisoners file suit against the facility where they are incarcerated. If at first their suit is dismissed because a court does not believe that the harm would be severe enough to be unconstitutional, it would make no sense to prevent the same prisoners from bringing a later suit if time and experience eventually showed that prisoners were dying from contaminated water."

In Texas, anti-abortion lawmakers vowed to continue to fight against the procedure.

"I am extremely disappointed with the Supreme Court's ruling today," said state Sen. Konni Burton, a Republican who replaced Davis in the state Senate. "However, members of the Texas Legislature like myself, who believe deeply in the value of every human life, will not yield in our efforts to provide the highest quality healthcare for women and our continued promotion of a culture of life."