With e-cigarettes and flavored vapes booming in popularity, the U.S. Supreme Court on Monday will examine whether the Food and Drug Administration unlawfully blocked the marketing and sale of more than a million new sweet and candy-flavored nicotine products in recent years.

The FDA has rejected applications for more than 1 million fruit, candy and dessert-flavored e-cigarettes and vaping liquids in recent years.

Other conservatives seemed more skeptical, wondering if the FDA had failed to give companies fair notice of what kind of evidence it required to approve flavored vapes. The case puts the FDA's role in approving new tobacco products under the microscope at ...