(NewsNation) — The U.S. Supreme Court overturned the landmark 1973 Roe v. Wade case, ending constitutional protections for abortion that had been in place for nearly 50 years.

The court, in a 6-3 ruling powered by its conservative majority, upheld a Mississippi law that bans abortion after 15 weeks. Justice Samuel Alito, in the final opinion issued Friday, wrote that Roe and Planned Parenthood v. Casey, the 1992 decision that reaffirmed the right to abortion, were wrong the day they were decided and must be overturned.

Authority to regulate abortion rests with the political branches, not the courts, Alito wrote.

Joining Alito were Justices Clarence Thomas, Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett. The latter three justices were appointed by former President Donald Trump. Thomas first voted to overrule Roe 30 years ago.

“It just stuns me,” President Joe Biden said in remarks from the White House following the Supreme Court’s decision. “It’s a sad day for the court and for the country.”

“The health and life of women in this nation is now at risk,” he said. “This is an extreme and dangerous path the court is now taking us on.”

The opinion comes from the case Dobbs v. Jackson Women’s Health Organization. Mississippi is one of several states that enacted a ban on abortion after 15 weeks. Friday’s outcome is expected to lead to abortion bans in roughly half the states.

The 1973 Roe decision implemented a tier system for allowing safe abortion access. Tier One covers the first trimester of pregnancy and only requires basic safeguards for health. Limits on abortion access are not allowed.

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Tier Two goes from the first trimester to the point of “fetal viability” or when the child can survive outside the uterus. That point is roughly about 24 weeks into the pregnancy. The state can only limit abortions to protect the mother’s health.

Tier Three goes from fetal viability until birth. In this tier, the state can restrict abortion as long as procedures are allowed when the mother’s life is at risk.

More than 90% of abortions are performed in the first 13 weeks of pregnancy, well before viability, according to the Centers for Disease Control and Prevention.

The 1992 Casey ruling reaffirmed Roe, but did away with the framework based around trimesters and instead created an “undue burden standard.”

Thirteen states, mainly in the South and Midwest, already have laws on the books that ban abortion in the event Roe is overturned. Another half-dozen states have near-total bans or prohibitions after 6 weeks of pregnancy, before many women know they are pregnant.

A draft of the opinion was released by Politico last month. The draft opinion in question suggested the Supreme Court was set to overturn the landmark case.

Chief Justice John Roberts confirmed the authenticity of the draft opinion and said he had ordered an investigation into what he called the “egregious breach of trust” in leaking the draft document. It is still unknown how the draft opinion leaked.

The Associated Press contributed to this report.