Let me say this- our President tells us that this must be done this way, because the right way takes too long (despite needing not more than approval of the attorney general which gives 72 hours before needing to seek a warrant to continue). Perhaps this is true- wonderful.
The Government of the United States was designed to be a slow moving behemoth- for good reason. There needs to be time for information to percolate, for the citizens to review the actions of their government, to debate them, and eventually act on them. The most efficient form of government, with the lowest turn around time, and the quickest to respond to threats is, and always will be, a dictatorship.
It has been more than four years since 3,000 Americans were killed by terrorists. In that four years, how many Americans have been killed by terrorists since? Don't count US troops or state-sponsored mercenaries in Iraq and Afghanistan- those are war zones and there are no terrorists in a war zone- only insurgents, partisans, and guerillas. Doesn't seem like much.
How many citizens have been spied on? Hundreds, maybe a few thousand, and all of them had ties to terrorists- so our executive branch tells us. By clear arithmetic, we've maintained the moral high ground here- they killed thousands, we spy on a few hundred to keep them from killing again.
Oh, but that's not the harm. The harm isn't in the spying. The key to the harm is the destruction of the Separation of Powers- that is being destroyed. Without that thin protection against a government gone wrong we have nothing. Our property could become forfeit, our freedom, and our lives, all in the name of "fighting terrorism". The power being concentrated in the Executive Branch not only goes against the spirit of the Constitution, but against a literal interpretation.
The argument that War Powers justify this is spurious, and simply debunked. There is no war. None whatsoever. And on what grounds do I make this claim? There has been no Declaration of War. Without that official vote from Congress, there isn't a War. The wording in the Authorization to Use Military Force that that they did pass says the President may use "all means necessary" but does not put him above the Constitution, or declare a state of martial law. The President cannot go to war without approval from Congress. At that time, the powers of the Executive get increased dramatically. But Congress has not approved a war. The "War on Terror" is a war in the rhetorical sense, not in the legal.