As you correctly note, but fail to understand the implications of, it the President who must, by the powers deliniated to that office by the Constitution, preserve and protect the "peace" of the nation. That is why matters of foreign policy, maintaining the national defense structure and foreign intelligence lie, Constitutionally, within the province of the Commander in Chief. It is opposite of prudent, necessary or "constitutional" that the Commander in Chief act as if the world is at "peace" with us simply because some foreign agent has not yet acted so as to create a need for Congress to "declare war". In fact, the Commander in Chief has every constitutional obligation to prevent foreign interests from being able to initiate such acts, before they happen, before any need for Congress to "declare war" arises. That was the whole premise of the 9/11 commission fiasco - how did we fail to "maintain the peace". That is what the purpose of a national defense structure and national intelligence operations are for. Congress can refuse to fund those structures, legislate ways in which they ought to be structures, refuse to approve the President's appointments to those structures, ask questions (hold hearings) about their operations, to better ascertain the appropriateness of requested funding, but Congerss does not operate them, does not manage them, does not run them over the head of the President and they have no power to. The DOD is not a Congressional operation.
As Boot Hill reminds you more eleoquently and thoroughly than I - congress can "declare war", but maintaining the defensive posture of nation, which includes foreign intelligence, is the Constitutional role of the Commander In Chief and it must operate and defend the nation from potential enemies whether or not there is a declared war. And, it is from the actions and by the powers of the Commander in Chief that the Constitution expects those defensive efforts to be conducted, not Congress.
We're told we're in a state of war so that the explicit and clear language of the 4th Amendment requirement that no warrants shall issue "but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized" does not apply...in other words, the President's authority as commander in chief of the armed forces conveys authority to ignore the 4th Amendment during wartime.
The 4th amendment requirement has been, continuosly, interpreted as relavent to "law enforcement" activities and not to the collection of foreign intelligence. The NSA and all the "electronic signals" information it collects could not even exist, in practical terms, under your misguided idea of applying the "warrants" clause of the 4th amendment to foreign intelligence. The fact that one-half of a conversation, to or from, a suspected foreign operative, begins or ends on United States soil does not consitute "domestic spying", anymore than FDR's intercepting of all telephone communications leaving or coming into the United States, to or from Japan or Germany, constituted "domestic spying". What J.Edgar Hoover and Bobby Kennedy did without warrants in the case of Martin Luther King constituted "domestic spying", an abuse of federal powers in law enforcment and was in violation of the intent of the 4th amendment requirement for a warrant; but Bobby's warrantless intercepts of conversations between Castro and phone locations in the United States was not.
You have this matter 180 degrees off balance. It is politicians in Congress and their little bruised egos, lacking the Constitutional powers of the Commander Chief, who have continually tried to limit the powers that the Constitution and the founders deliniated to the chief Executive. The "dictator" charge is always dragged out by the little dictators in Congress, deflecting from the fact that the President and the President's successors are and will be the highest elected officials in the nation, representing all the people. That is why the people, in have generally supported their Presidents in matters of national intelligence issues, preferring an active defense to a timid, bumbling and ineffectual congress. In fact, the national leaders who have historically made the grade, in the eyes of the people, were leaders who, whether in war or in peace, led the country, above following Congress. Weak Presidents, like Carter and Clinton have, by historians and the people, failed to make the top grades, and rightly so - they failed to "actively" defend the nation.
Even searches "without probable cause" can be constitutional "when special needs, beyond the normal needs for law enforcement make the elements of a warrant and probable cause requirement impracticable." Ver- onia School District 47j v. Acton, 515 U.S. 646, 653 (1995)
United States v. Clay, 430 F.2d 165 (5th Cir. 1970). The court held that a federal statute could not forbid the President from ordering wiretappeing when gathering foreign intelligence in the national interest. Thus FISA is unconstitutional to the extent it is trying to limit the President's own power under the Constitution.