It's been determined to be legal.
I'm not subbing to this thread because I could argue for hours on it, but I thought I should mention this: your statement isn't completely true.
It has both been determined legal and unconstitutional by New York courts. There's an excellent and lengthy opinion on the side of freedom that basically says that the judge could not use, as his North Star, a case which predates the rise of cellphones to judge this case. I think the fact that this has been found both ways sets up a likely Supreme Court ruling, but who's to say that they'll get it right this time? I've not been a fan of most of their rulings regarding the 4th.
While I'm at it I should note for the thread that our country was founded on principles and that, though they may be 200+ years old, their existence is paramount to what makes us who we are as a nation. People seeking to take such things from you wish to do so slowly. And people who don't pay attention, give them up. Innocence is also highly regarded in our country (or at least it was). That is how people can be trusted with guns, searches, speech, etc. We are innocent until proven guilty. The government is increasingly switching that and forcing the burden of proof onto the individual.
One of the most insightful responses to the "nothing to hide" argument in this thread was that if we aren't doing anything wrong, why can't we have privacy? Privacy is enshrined in the 4th Amendment and in our unalienable rights of life, liberty, and the pursuit of happiness.
Sorry, I would have thought Patrick Henry's quote about liberty and death would still resound amongst Americans. But this dumb "nothing to hide" argument clearly shows that we're apparently not content with our own privacy and simultaneously so afraid of terrorism that we think the government deserves its privacy and ours as well. The capacity for doublethink in the human mind is astounding.
I should also mention that I find it funny when someone brings up free markets and someone else says that we've tried it. Yep, we did. It wasn't in 2008 or the 80s or the 50s as they imply. It was mostly pre-19th century and it was responsible for making us a superpower. But keep thinking that we have free markets and "evil" corporations. You'll never grow out of it (unless maybe you own a business ever). But that's how it is. It's always about oppressors vs the oppressed to liberals, civilization vs barbarism to conservatives, and freedom versus coercion for Libertarians. I'll always choose the latter scenario because I value freedom above all, but you're free to give it up. Just do me a favor, give up your own freedom and stop trying to legislate mine away.
That is all.