As giant abortion provider Planned Parenthood celebrates its 100th anniversary this week, pro-lifers led by The Stream are commemorating #100forlife to remember all who have died due to abortion.

It comes forty-three years after the U.S. Supreme Court legalized abortion in Roe v. Wade — permitting abortions during the three trimesters of pregnancy, and allowing greater regulatory power by states during the second and third trimesters. To come up with this odd, three-tier ruling, the court relied upon a tortured interpretation of the U.S. Constitution, finding in the “penumbras” of the Constitution a right to privacy fundamental to the concept of liberty.

While abortion remains legal in the U.S., the laws governing it have changed significantly in recent years. Some of those modifications are state laws that impose additional requirements before having an abortion, or restrictions on when or how an abortion may be procured. Most of the laws came as the focus of the pro-life movement expanded from abortion center protests and sidewalk counseling to include passing state and federal legislation.

The movement was emboldened to take this route by Gonzales v. Carhart in 2007, in which the Supreme Court upheld a nationwide ban on partial-birth abortions.

These laws, which added new requirements and regulations for abortions, have successfully resulted in the shutdown of abortion centers. Five states now have only one abortion facility. According to the abortion rights research organization Guttmacher Institute, in the late 1980s, there was a high of 705 centers nationwide. By 2011, that number had dropped to 583, and others have closed since.

The laws may also be contributing to a decrease in the number of abortions. The Guttmacher Institute reported a high of 1,590,750 abortions in 1988. That number has declined almost every year since then, to 1,058,490 in 2011, equivalent to the level in the mid-1970s shortly after abortion was legalized.

Significant Supreme Court Victories That Reversed the Abortion Trend

Since Roe v. Wade, there have been several Supreme Court decisions that struck down or upheld state laws regulating abortion —  overall, in balance favorable to the pro-life movement. In the 1980 decision Harris v. McRae, the court upheld the constitutionality of the Hyde Amendment, which prohibits most federal funding of abortions, except in the case of rape, incest or danger to the mother’s life.

Nine years later, in Webster v. Reproductive Health Services, the court upheld Missouri’s ban on the use of public facilities and employees for abortions, and the state’s requirement that doctors test for fetal viability at 24 weeks.

A Supreme Court case in 1992 dealt the biggest blow to Roe v. Wade. In Planned Parenthood v. Casey, the court backed off from the convoluted, messy Roe precedent prohibiting states from regulating abortion during the first trimester. It permitted states to implement laws requiring such things as pre-abortion counseling, waiting limits and parental consent, so long as the requirements did not impose an “undue burden” on women.

A Legal Setback in 2016

Despite years of strides, the pro-life movement suffered a significant defeat in June when the high court struck down two abortion center regulations in Texas. In Whole Woman’s Health v. Hellerstedt, the court invalidated laws that required abortion doctors to have admitting privileges at nearby hospitals and held abortion facilities to the standards of outpatient surgical centers. The court held that the onerousness of the regulations outweighed the state’s interest in regulating health.

Will the Generally Pro-life Trend Continue?

The Supreme Court ultimately has the final say, rightly or wrongly, on abortion laws. Whether pro-life advocates will be able to continue the trend of stripping away parts of Roe v. Wade depends on the future makeup of the Court. If Democrat Hillary Clinton becomes president, she will appoint left-leaning justices who will make up a majority of the court and strike down pro-life laws. If Republican Donald Trump wins the election, he has promised to appoint mostly right-leaning justices who will have the opposite effect.

Check out #100ForLife on Twitter. Follow Rachel on Twitter at Rach_IC.

(Guttmacher Institute)