[i_robot73]

Then why, for all these years, was it necessary to has a warrant for a phone tap?

If you using the services of a 3rd party...as you state.

[Alberta's Child]

That's a good question. The difference was that warrants were always required for phone taps because the intent was to listen in on a conversation as it was taking place.

What's changed in the modern age of cell phones is that these phones continually generate data that gets uploaded to the phone carrier and stored indefinitely. That was the important legal distinction in this case, and it was the basis of the dissenting opinion by Thomas, Gorsuch, etc. They determined that a warrant wasn't required because getting data from a phone company months or years after the fact is no different than getting copies of your financial records from your bank.