>> reporter: good morning. it's more than a year after donald trump stunned the world and caused chaos in the airports, and the supreme court is finally taking up the legality of the travel ban. it concerns the third version of the ban. it was signed in september and bans travel to various degrees from seven countries. in december, the supreme court allowed the entire ban to take effect pending this appeal. the challengers argue that it violates immigration law and the constitution. they say the president exceeded his authority, and it has no national security justification. they say the president demonstrated animus to muslims in the tweets he sent out in his campaign statements. the government says the ban is necessary to protect national security and says it's neutral toward religion. it's worth noting this is the first major trump administration policy the court's going to hear, and it comes on the last day of arguments of the term.