WASHINGTON (Nexstar) — The U.S. Supreme Court is hearing oral arguments on two challenges to Texas’ restrictive abortion law.

The law that prohibits abortions once cardiac activity is detected, which could be as early as six weeks into a pregnancy, went into effect in September.

But the justices aren’t considering the constitutionality of the right to an abortion but rather how the Texas law was structured.

Hundreds of pro-life and pro-choice protesters gathered outside the Supreme Court Monday.

“This is a really crucial moment,” said Jamie Manson with Catholics for Choice.

Manson says the high court’s ruling could set the tone for future cases on abortion rights.

“We have a disproportionately Catholic Supreme Court. Six of nine justices are Catholic and of those six, five are very, very right wing conservative Catholic,” Manson said.

The justices will decide the fate of the Texas law, which is enforced through civil lawsuits that can be brought against anyone who helps a person get an abortion.

U.S. Solicitor General Elizabeth Prelogar argued “no constitutional right is safe” if the justices allow the law to stand.

“Our constitutional guarantees cannot be that fragile, and the supremacy of federal law cannot be that easily subject to manipulation,” Prelogar said.

Texas Solicitor General Judd Stone defended the law, saying abortion providers are suing the wrong people, since the law is enforced by private citizens, not the state.

But that defense met some resistance from even conservative justices like Brett Kavanaugh.

“There’s a loophole that’s been exploited here or used here,” Kavanaugh said.

Mark Heron, senior counsel with the Center for Reproductive Rights, says he was happy to hear that.

“We’re pleased obviously several of the justices had concerns about the broad implication,” Heron said.

The Texas law will stay in effect until the Supreme Court issues its decision.