This guarantees to United States citizens their God-given rights of liberty (you know, part of that lovely triad of "life, liberty, and pursuit of happiness") by preventing them from being arrested and held indefinitely. It's rarely infringed upon for our citizens--most notably, in cases where people call child illfare's anonymous child abuse hotline ("to be confronted with the witnesses against him") instead of the local police who are supposed to be the first in the door to determine if an investigation is needed--but it also happens when a war on (some) drugs "sting" gets too arrest happy with people who are just in the wrong place at the wrong time.
While this amendment isn't abused often against those whose rights it's in place to protect, it is abused by being applied to those who are not United States citizens.
No one who is not a United States citizen is entitled to any protection by the U.S. Constitution, nor by any of its amendments. Sure, it's nice that most of the time, anyone on U.S. soil can speak their opinions freely, or attend the church they want to. However, that's a visitor's privilege. Act up on our soil, and they really should lose that privilege: detain them and put them on the first flight heading back to wherever they came from, at the very least. It is their God-given right to speak and to believe as they wish, yes, but without being citizens of the United States, they shouldn't have that right protected by our government.
Especially not in cases where the individual claiming Constitutional protection attacked this nation. Not one terrorist deserves protection under the fourth, fifth, sixth, or eighth amendment--unless born or naturalized as a United States citizen. And those are few and far between.* Either lock them up somewhere with no amenities (unlike Guantanamo Bay), shoot them in the head and be done with it, or put them on a plane back to whatever pestilent shithole spawned them.**
*For now. As far as we know.
**Were I in charge, I'd tell the pilot and crew to bail out, then take it out of the sky in a lovely fireball...with a missile coated in pig fat.