Davis (D) and Glover committed a string of gas station robberies. A federal prosecutor charged both men with multiple counts of robbery affecting interstate commerce in violation of the Hobbs Act, 18 U. S. C. §1951(a), and one count of conspiracy to commit Hobbs Act robbery. D was also charged with being a felon in possession of a firearm. D was acquitted of one robbery charge and both were found guilty on all the remaining counts. These convictions authorized the court to impose prison sentences of up to 70 years for D and up to 100 years for Glover. P also pursued charges under §924(c) which authorizes heightened criminal penalties for using or carrying a firearm “during and in relation to,” or possessing a firearm “in furtherance of,” any federal “crime of violence or drug trafficking crime.” It defines the term “crime of violence” in two subparts-the first known as the elements clause, and the second the residual clause. A crime of violence is “an offense that is a felony” and “(A) has as an element the use, attempted use, or threatened use of physical force against the person or property of another, or “(B) that by its nature, involves a substantial risk that physical force against the person or property of another may be used in the course of committing the offense.” It carries a mandatory minimum sentence of five years in prison, over and above any sentence received for the underlying crime of violence or drug trafficking crime. The minimum sentence rises to 7 years if the defendant brandishes the firearm and 10 years if he discharges it. A defendant who uses a short-barreled shotgun faces a minimum sentence of 10 years. And repeat violations of §924(c) carry a minimum sentence of 25 years. P argued that Ds each committed two separate §924(c) violations by brandishing a short-barreled shotgun in connection with their crimes. These convictions yielded a mandatory minimum sentence for each man of 35 years, which had to run consecutively to their other sentences. The district court ultimately sentenced Glover to more than 41 years in prison and D to more than 50 years. Ds argued that §924(c)’s residual clause is unconstitutionally vague. The Fifth Circuit eventually held §924(c)(3)(B) unconstitutional. It held that the charge of robbery as a predicate crime of violence could be sustained under the elements clause. It then held that the charged conspiracy as a predicate crime of violence, depended on the residual clause; and so it vacated Ds' convictions and sentences on that count. This appeal resulted.