Chris McDaniel has a friend, who thinks Bush v. Gore will help McDaniel win

Basically, in the first point he suggests that the Mississippi Supreme Court is inventing the deadline without a statutory basis, and, because the rules governing elections to Congress are assigned by the Constitution to the state legislatures alone, the courts can’t… well, can’t construe them, other than “strictly.” This amounts to trying to inflate the “there’s no deadline in the statute” into a constitutional argument. That’s at least an interesting argument.

Question: Can amici come up with an argument not even hinted in the brief of the party they support? I know it’s a comment thing for them to argue facts and the like in support, but can they raise a new legal issue?