Many would argue that modern day Islam is more of a military organization than a religion. In that case a change to the Constitution may be in order.
No need to amend the Constitution. Just have the Attorney General declare Islam a criminal organization and apply all applicable RICO statutes.
I'm sure the authorities have dealt with fake religions before.
Oh, come on, give me a break.
They have,
but the Branch Davidians didn't have any bombs.
And, they were a sect, not in the process of subjugating everyone around them.