Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, acknowledged the possibility of an extended campaign, as the military announced that six U.S. service members had been killed so far.
The president said he accepted the invitation "in honor of our nation's 250th birthday," and will make it the "greatest, hottest and most spectacular dinner of any kind, ever."
The case is the second major Second Amendment one before the high court this term. In the first, justices heard arguments in a case challenging a Hawaii law limiting where licensed concealed-carry holders may bring firearms.