More Warrant Sauce…
Subchapture I warrant (FISA): Gov needs to demonstrate probable cause to believe that the "target of the surveillance is a foreign power or agent of a foreign power," that "a significant purpose" of the surveillance is to obtain "foreign intelligence information," and that appropriate "minimization procedures" are in place. This warrant is designed to capture terrorists; and allows active and passive surveillance, and can be applied retroactively in perpetuity. They can access info on everyone who had any type of contact with the subject (i.e. Carter Page) or within 3 hops of these people.
Title III warrant (Omnibus Crime Control and Safe Streets Act of 1968): Gov needs to demonstrate probable cause that the interception will reveal evidence that "an individual is committing, has committed, or is about to commit a particular offense" listed in § 2516 (see 5th link below). This warrant is much more restrictive and consistent with the Fourth Amendment. It is the most common and directed at citizens suspected of committing criminal activities.
https://it.ojp.gov/PrivacyLiberty/authorities/statutes/1286
https://www.law.cornell.edu/uscode/text/50/1804
https://it.ojp.gov/PrivacyLiberty/authorities/statutes/1284
https://www.law.cornell.edu/uscode/text/18/part-I/chapter-119
https://www.law.cornell.edu/uscode/text/18/2516