[rhombus]

Sorry to intrude. I don't know if you guys saw this

http://article.nationalreview.com/?q=ODgxN2VkMzA3MTFjNWFmNzZjNzZiODVlYzI3YTdiZTc=

Forgive me if it is old info for you guys.

[dirtboy]

Nice try, but the article all comes down to this point (as it steps through the fact that probable cause IS required in most cases) and comes to this:

A search unsupported by probable cause can be constitutional, we have said, “when special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.”

So, is it "impracticable" for the government to get calling data in this case by subpeona instead of getting all calling records from Verizon?

No. I can think of many ways that an expedited process can be set up to quickly provide calling data upon showing any level of probable cause. I would even be willing to set the probable cause bar very low in wartime. But getting the entire calling database is bereft of probable cause.