Substantial Confusion about Substantial Burdens

As the Supreme Court rev1s1ts the clash between religious belief and the Affordable Care Act (ACA) in the Zubik1 case, it is worth mulling over a key phrase in the law that governs that clash: \u27·substantial burden. According to the Religious Freedom Restoration Act (RFRA), the government must-provided it does not meet certain other conditions, such as showing a compelling interest-make an accommodation if it places a \u27\u27substantial burden\u27\u27 on a person\u27s religious exercise.2 If the question in the Hobby Lobby case was whether a for-profit corporation could be a \u27\u27person that \u27\u27exercised religion, 3 the question the Court now faces is whether the government has in fact \u27\u27substantially burdened some religious non-profits in trying to accommodate their objection to the contraceptive mandate.4 But what is a \u27\u27substantial burden ? Or to put it another way, what makes a burden substantial? What follows is my best effort to provide clarity-in the form of a primer-as to the meaning of substantial burden under RFRA