The outcome of this potentially monumental dispute could keep the world safe or plunge it into sudden and unexpected conflict -- with catastrophic consequences.
Since 9/11, American presidents have been operating under the assumption that they could effectively take the nation to war with virtual impunity. Now, Donald Trump has tried to enshrine this concept in a secret memo without any approval by Congress.
Kaine said he was "concerned that this legal justification may now become precedent for additional executive unilateral military action," and singled out "an extremely risky 'bloody nose' strike against North Korea."
The memo is only the latest act by Trump that would appear to give him all but unfettered authority beyond his whim or declaration to take the US into a conflict.
The fear is that a thoroughly erratic president could, in a moment of pique order, or even as a distraction, embark on an adventure that would set the nation and the world on an irreversible course that Congress would be powerless to halt.
The still-undisclosed powers contained in the Trump memo could spark unanticipated skirmishes like the ambush in Niger last October, leaving dead Americans in their wake. At the other end of the spectrum, they might unleash events that could lead potentially to a nuclear holocaust.
The President has already opened the question
of whether he'd violated the limit of his war-making powers by his military actions in Syria.
Last April, following evidence of the use of chemical weapons against his own people by Bashar al-Assad, Trump ordered a strike by 59 Tomahawk cruise missiles
that seemed to have had little lasting effect beyond solidifying Russian support of the Syrian dictator.
Trump's action was in sharp contrast to that of President Obama, who threatened to launch a strike on Syria for similar use of such weapons but backed off at the last minute in the absence of congressional authorization, which he recognized he was most unlikely to receive.
In each case, the presidents had set up a "red line" which, if the enemy crossed it, would be met by a sharp military response.
I'm heading up a project at the Center on National Security of Fordham Law School on red lines and their anatomy -- when they might be effectively used and when they are grossly misused. Obama's refusal to react to Syria's abuse of chemical weapons called into question the red line he had established, a line that Assad leaped across with impunity since he was met with no military response.
This may well have led Assad to believe he could cross such a red line again, but did not count on Trump's willingness to act on his own authority to attack, with little thought to his constitutional limitations.
In fact, the issue is vastly more complex.
Bruce Ackerman, Sterling Professor of Law and Political Science at Yale, observed in an interview that the issue of such red lines and presidential authority to attack dates back to Thomas Jefferson and his action against the Barbary Pirates in 1801
More recently, and pertinently, we have an example from 1973, when Congress passed the war powers resolution. At that time, in reaction to Richard Nixon's expansion of the Vietnam War, Congress spelled out in some detail just what rights the President has to mount an offensive operation -- effectively 60 days to send in troops, then in the absence of Congressional approval, another 30 days to withdraw.
One key issue is when this 60-day period begins. Ackerman, and many other legal scholars, hold that "hostilities begin when there is an imminent danger."
In the critical case of North Korea, Ackerman contends the clock started when President Trump declared the existence of such a danger in a speech to the United Nations last September 19, which would mean his opportunity to bloody Kim's nose, without Congressional approval, ran out on November 18.
Of course, if the North Korean despot were to launch his own offensive attack on any American facility or territory, all such restraints are instantly removed and Trump would have the right to respond, as he has threatened, with full "fire and fury."
Enter, now, the secret memo that may give Trump broad authority to act on any whim, a document to which only a small cadre in his administration are privy.
The timing is especially acute, as the nation's intelligence chiefs told a Senate hearing Tuesday
that Kim Jong-un was planning more missile and nuclear weapons tests this year -- though likely no direct offensive against the US.
The concern of an increasingly broad spectrum of Trump opponents is that the President has been effectively setting up a succession of red lines that could lead to him suddenly and unilaterally declaring had been crossed.
There have been threats to China in the South China Sea; Iran and its spreading influence in the Middle East; and in the case of North Korea, a "bloody nose" to teach Kim Jong-un a lesson. Any of these could quickly develop into full-blown nuclear war.
What this means is that Trump's war powers memo, appropriately scrubbed for any classified "sources and methods," needs to see the full light of day, deserves a full national debate and discussion, even Congressional action.
It is bad enough that the President has virtually unfettered access to the nuclear launch codes. Any other means of inflicting an ill-advised "bloody nose" must be restrained at all costs if the nation and the world is not to be plunged into an irreversible conflict of catastrophic proportions on an ill-advised whim.