[Sandy]

there is no '"agent of a foreign power" exception' for warrantless surveillance under FISA.

Yes there is. Section 1804 (plus the other 72 hour emergency provisions elsewhere in the act, but 1804 is the primary section).

1802 provides for warrantless surveillance of a "foreign power" per 1801(a)(1) - (3)

Actually, 1802 provides for surveillance without a court order. 1804 provides for surveillance with a court order. "Court order", not "warrant". There's a significant difference. Look at FISA again and notice that it provides for nothing but warrantless searches. The word "warrant" isn't in there anywhere, other than in some definitions where it says things like "and a warrant would be required for law enforcement purposes". FISA court orders are specifically not warrants. They're fishing permits, which is exactly what the 4th Amendment's Warrant Clause forbids.

[Cboldt]

there is no '"agent of a foreign power" exception' for warrantless surveillance under FISA.

Yes there is. Section 1804 (plus the other 72 hour emergency provisions elsewhere in the act, but 1804 is the primary section)

Looking ahead to your comment that "warrant" does not equal "court order," I note that section 1804 describes the requirements for an application for a court order. Section 1804 does not describe the circumstances where a court order is not "required." I put that in quotes to differentiate between FISA "requirements" and Constitutional "requirements."

Actually, 1802 provides for surveillance without a court order. 1804 provides for surveillance with a court order. "Court order", not "warrant". There's a significant difference.

I think the difference is semantic. "Court order" being a generic term and all. Some of the requirements for an application under 1804 are:

• the identity, if known, or a description of the target of the electronic surveillance
• a statement of the facts and circumstances relied upon by the applicant to justify his belief that the target of the electronic surveillance is a foreign power or an agent of a foreign power
• a statement of the facts and circumstances relied upon by the applicant to justify his belief that each of the facilities or places at which the electronic surveillance is directed is being used, or is about to be used, by a foreign power or an agent of a foreign power
• a detailed description of the nature of the information sought and the type of communications or activities to be subjected to the surveillance
• a certification or certifications by the Assistant to the President for National Security Affairs or an executive branch official or [officials designated by the President, and subject to advice & consent of the Senate for their office] that:
  • that the certifying official deems the information sought to be foreign intelligence information
  • that a significant purpose of the surveillance is to obtain foreign intelligence information [Note, not "primary purpose"]
  • that such information cannot reasonably be obtained by normal investigative techniques
  • that designates the type of foreign intelligence information being sought according to the categories described in section 1801
• a statement of the period of time for which the electronic surveillance is required to be maintained

Likewise, Title III surveillance (for criminal purposes, as opposed to foreign intelligence purposes of FISA) is conducted under what the statutes refer to as "court orders" too. See 18 USC 2516 and 18 USC 2518.

At any rate, I have no objection, if it suits your fancy, to substitute the term "without a court order" for "warrantless." And, for what it's worth, evidence properly obtained under 18 USC 2510 et seq is within the boundary of 4th amendment protection.