The u. s. constitution regularly allows ex post facto laws.

a. True

b. False

Ex post facto laws are when a law is passed making something illegal that was legal before and they try to punish someone who did in before the law was passed. Say you went and ate an icecream cone. The next day, the senate passed a law that said it was illegal to eat icecream cones. It would be illegal for them to arrest you for eating the icecream cone because the law wasn't yet passed. So the answer is false.