Anti-abortion supporters outside the U.S. Supreme Court in Washington onTuesday, March 20, 2018. (AP Photo/Andrew Harnik)

California's law that requires “pro-life” pregnancy centers to inform clients about abortion appeared to be in jeopardy Tuesday after arguments before the U.S. Supreme Court.

The case of National Institute of Family and Life Advocates v. Becerra drew more than 100 demonstrators on both sides of the abortion debate in front of the court. Dozens of people camped out starting Monday to secure a seat for the hourlong argument.

The pregnancy centers, backed by Alliance Defending Freedom, claim that the law amounts to compelled speech, in violation of the First Amendment's free speech clause. The same conservative group is also backing a similar First Amendment challenge in the pending case of Masterpiece Cakeshop v. Colorado Civil Rights Commission.

Here are three highlights from the argument:

➤ Kennedy Is Key: If, as usual, Justice Anthony Kennedy casts the deciding vote, it looks like he would strike down the California law. He offered a hypothetical: “What would happen if an unlicensed entity, unlicensed center, just had a billboard that said 'Choose Life.' Would they have to make the disclosure?” ADF president Michael Farris responded yes, adding that the disclosure about abortion options would also have to be the same size and in multiple languages. Using a phrase often associated with striking down abortion restrictions, Kennedy responded, “It seems to me that that means that this is an undue burden … that should suffice to invalidate the statute.” Justice Samuel Alito Jr. also seemed hostile toward the law, while others in the conservative majority did not tip their hand.

➤ Goose v. Gander: Several liberal justices—but not enough for a majority—suggested that if the California law is unconstitutional, so too should be the laws in other states that require abortion providers to inform patients about adoption and other alternatives to abortion. “In the law, as you well know, what is sauce for the goose is sauce for the gander,” said Justice Stephen Breyer. Justice Elena Kagan said the California law is the “exact flip side” of such “informed consent” laws, which were upheld in the 1992 case Planned Parenthood of Southeastern Pennsylvania v. Casey. Farris said those laws were different from California's because they involved medical intervention rather than counseling.

➤ Gerrymandered Statute: Farris repeatedly said that the California law was “gerrymandered” to single out certain individuals and facilities who had to make the required notifications, while others did not. Kagan picked up on the unusual reference, stating that “if the [statute] is gerrymandered, that's a serious issue—in other words, if we have these general disclosure requirements, but we don't really want to apply them in general, we just want to apply them to some speakers whose speech we don't much like.” Deputy California Solicitor General Joshua Klein insisted that the law was not targeted toward “any particular viewpoint. But the fact that Kagan raised the question suggested that her vote might be in play.