As a lawyer, it's a no-brainer, both the normative (should) question, and the positive (way it is) question: The 4th amendment requires probable cause, which means warrant - this privacy right is foundational to our free society and critical to maintaining it.

I have friends in law inforcment that have told me the difficulty in obtaining a warrant. If i had a family member in danger I would not want the possibility of a tragedy due to this . All these comments are evidently from people who have never actually experienced a scenario such as this

Judge written order.

The Fifth Amendment to the US Constitution protects accused from self-incrimination. I say cell phone data should be included.

It is called the "rule of law." The 18th century, "Age of Enlightenment," Constitution we rely on to guide us through these legal tangles is totally unfit to help us in the 21st Century. Only by using tortured interpretations of the existing language can courts make decisions about these things. It is time to write a new Constitution based on secular humanist and democratic socialist ideals and principles.

Cell phone records should be available to law enforcement. However, if law enforcement uses it for any purpose than investigation of a known or suspected crime. But, any other use of cell phone records by law enforcerment should be a serious felony for the officers perpetrating that offense.

Need a warrant.
LEO's/prosecutors should have probable cause enough to obtain a warrant from a judge so they can collect data.

Always a warrant requiring probable cause. They can't go through printed correspondence without a warrant, and I fail to see how private digital formats change that requirement.

Get a warrant first!

I think it's a crucial step in catching some criminals, but I don't want it used to take someone down that is normally a good citizen.