With historic abortion arguments behind them, the justices will soon begin the work of crafting a decision that could significantly limit abortion rights in the United States.

They will meet privately before the end of the week to take an initial vote on whether to uphold Mississippi’s abortion ban after 15 weeks of pregnancy. However, it will be months before a decision is made.

During nearly two hours of oral arguments on Wednesday, the court’s conservative majority indicated that it would uphold the Mississippi law and allow states to prohibit abortions much earlier in pregnancy. The court could even overturn a nationwide right that has been in place for nearly 50 years.

Hundreds of protesters chanted for and against the justices as they heard arguments that could determine the fate of the court’s historic 1973 Roe v. Wade decision legalizing abortion throughout the United States, as well as its 1992 ruling in Planned Parenthood v. Casey, which reaffirmed Roe.

The outcome will most likely not be known until next June. However, after nearly two hours of deliberation, the six conservative justices, including three appointed by former President Donald Trump, indicated that Mississippi’s law would be upheld. At the very least, such a decision would jeopardize Roe v. Wade, which allows states to regulate but not prohibit abortion up to the point of fetal viability, which is around 24 weeks.

There was also strong support among the conservative justices for the abolition of Roe and Casey. Justice Clarence Thomas is the only member of the court who has openly advocated for the two cases to be overruled.

Justice Brett Kavanaugh, a Trump appointee, questioned whether the court would be better off withdrawing from the abortion debate entirely and allowing states to decide.

According to the Guttmacher Institute, a research organization that supports abortion rights, if Roe and Casey are overturned, abortion will soon become illegal or severely restricted in roughly half of the states. Depending on the Supreme Court’s decision, legislatures in many Republican-led states are poised to act. The U.S. Court of Appeals for the Sixth Circuit vacated previous rulings that had blocked a Tennessee law that included a ban on abortions once a fetal heartbeat was detected — roughly six weeks — and ordered a rehearing by the full court on Wednesday.

Proponents of abortion rights argue that people of color and those with lower incomes would be disproportionately affected.

The court’s three liberal justices stated that overturning Roe v. Wade would severely damage the court’s legitimacy.

In unusually strong language for a high-court argument, Justice Stephen Breyer warned his colleagues that they “better be damn sure” before tossing out established abortion decisions. Public opinion polls show that people want Roe v. Wade to be overturned, though some polls also show that people want more restrictions on abortion.

Chief Justice John Roberts appeared to be the most interested among the conservatives in a less sweeping ruling that would uphold Mississippi law but not explicitly overrule Roe and Casey.

According to the federal Centers for Disease Control and Prevention, more than 90% of abortions are performed within the first 13 weeks of pregnancy, well before viability.

At Mississippi’s lone abortion clinic, the Jackson Women’s Health Organization, about 100 patients per year have abortions after 15 weeks. After 16 weeks, the facility does not perform abortions. Even if the 15-week ban is upheld, the decades-old viability line would be rejected. Proponents of abortion rights argue that this would effectively overturn Roe and leave no principled line for when abortions might be prohibited.

Another Trump appointee, Justice Neil Gorsuch, suggested that the lack of a rigorous alternative might be a reason to overrule Roe and Casey entirely.

Both sides of the abortion debate crowded the sidewalk and street in front of the court, their opposing rallies audible even from inside the building. “Her Body Her Choice” and “God Hates the Shedding of Innocent Blood” were among the opposing signs. The court increased security measures, including closing off some streets surrounding the building.

Perhaps in recognition of the gravity of the issue before them, the justices took the bench at 10 a.m. with no smiles or private jokes.

The case was heard by a court with a 6-3 conservative majority that has been transformed by Trump’s nominees, Gorsuch, Kavanaugh, and Amy Coney Barrett.