WASHINGTON—The nuns in the Little Sisters of the Poor, who run nursing homes for the elderly poor, had been praying around the clock for their case when they arrived at the Supreme Court early Wednesday morning and sat down for breakfast in the court’s cafeteria. Two Catholic University of America law students, Jason Miller and Will Russell, had camped out in sleeping bags all night to get a seat in the arguments.

WASHINGTON—Four years of lawsuits from religious nonprofit groups culminate in a Supreme Court case Wednesday testing the contraceptive and abortifacient mandate of Obamacare, which the U.S. Department of Health and Human Services announced in 2010.

The death of a sitting Supreme Court justice in the middle of the court’s term is a rare event, and a death on a tightly divided nine-person bench in a presidential election year is potentially a political and legal powder keg. The leader of the court’s conservative wing, Justice Antonin Scalia, 79, died of apparent natural causes at a West Texas ranch on Feb. 13. Scalia was a devout Catholic, who had nine children with his wife of more than 50 years, Maureen McCarthy.

Kent and Rosaria Butterfield purchased a 2014 health insurance plan under the Affordable Care Act, even though it cost more and required them to change doctors. The plan worked fine, but a surprise awaited them at the end of the year: As an author and speaker, Rosaria’s unpredictable income had exceeded their sign-up estimate and triggered one of Obamacare’s many fines.

A California judge declined Thursday to force a Catholic hospital to facilitate a sterilization procedure for a woman who’s having a scheduled C-section at the facility later this month.

Rebecca Chamorro’s doctors had requested permission to do the tubal ligation immediately after delivering her baby, which is the safest and most convenient time to do the procedure. But Mercy Medical Center’s administrators refused, saying the sterilization violated the hospital’s Catholic beliefs.

Almost every kind of nonprofit that objects to the federal contraceptive and abortifacient mandate on religious grounds will have its day in court this March. The Supreme Court on Nov. 6 granted all seven pending petitions challenging the mandate, covering organizations helping the poor, advocacy groups, religious colleges, and religious health insurers.