The U.S. Supreme Court has reversed a lower-court decision upholding a California law requiring anti-abortion crisis pregnancy centers to more fully disclose what they are.

The case pitted the right to know against the right of free speech. On one side, self-identified "crisis pregnancy centers" that seek to prevent abortions, and on the other side the state of California, which enacted a law to ensure that these centers do not intentionally or unintentionally mislead the women who walk through their doors.

In a 5-to-4 ruling, the court said the centers are likely to succeed in their claim that the law violates the First Amendment. That overturns an earlier decision by the Ninth Circuit upholding the law, sending the case back for further consideration.

Writing for the majority, Justice Clarence Thomas said the law "targets speakers, not speech, and imposes an unduly burdensome disclosure requirement that will chill their protected speech."

Supporters of the California law called the state's effort nothing more than seeking "truth in advertising." But anti-abortion pregnancy centers saw the law as unconstitutional, compelling speech that turns them into mouthpieces for a government message they disagree with.

Passions run high when it comes to abortion. Add the fact that most anti-abortion pregnancy centers have a firm Christian perspective, and you have quite a volatile mix.

The case began in 2015 when California passed a law known as the FACT Act. (It stands for Freedom, Accountability, Comprehensive Care and Transparency.)

The impetus was two-fold — first, allegations that pregnancy centers opposed to abortion were using deceptive practices; and second, concern that lower-income women, in particular, weren't aware of the free pregnancy-related services California provides, from prenatal and delivery care to birth control and abortion.

The FACT Act requires unlicensed crisis pregnancy centers to post a sign or otherwise disclose to their clients in writing that the center is not a licensed medical facility and has no licensed medical provider who supervises the provision of services. The disclosure requirement extends to advertising, which anti-abortion pregnancy centers objected to as an attempt to "drown out" their message.

The second provision of the law, dealing with licensed centers, requires clinics that do not provide a full range of reproductive care, including services covered by Medicaid, to post a sign that says the state provides free or low-cost access to prenatal care, birth control, and other reproductive care, including abortion.

In recent years, the number of pregnancy centers that counsel against abortion has dramatically increased. Today there are about 2,700 of them around the country, more than three times the number of clinics that provide abortions.

And just as some states provide taxpayer funds for abortions, 14 states directly fund anti-abortion pregnancy centers. From 2001 to 2006, the centers received an estimated $30 million in federal funding.

There is no data on how many of the 2,700 anti-abortion pregnancy centers are unlicensed. But unlicensed clinics offer pregnancy tests, limited ultrasounds, and, to an unskeptical eye, they can look very much like a licensed medical facility.

The personnel wear surgical scrubs or white coats and ask clients to fill out medical history questionnaires. Indeed, many clinics locate next to or across the street from a full service women's reproductive health center and some use similar sounding names.

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