The reluctance to deploy large-scale ground troops has not stopped unilateral use of assassination by drone.
In recent history, both Barack Obama and George W Bush have manipulated language and legal precedent to authorize their unilateral use of force.
"It is clear now, and I mean it, that the unilateral use of force leads to failure," he said of the Iraq crisis.
Dr. ElBaradei said "the unilateral use of force by Israel" undermined "the due process of verification that is at the heart of the nonproliferation regime".
This goes far beyond anything allowed by the Charter, which restricts the unilateral use of force to self-defense against "armed attack".
This is nothing less than the repudiation of the United Nations Charter's effort to restrict unilateral uses of force to extreme cases, and to make collective, multinational security measures the norm.
In congressional testimony, the phrase "when we must" was explained more fully: the US is entitled to resort to "unilateral use of military power" to ensure "uninhibited access to key markets, energy supplies, and strategic resources".
The second time they faced each other the First Minister insisted he believed Scotland could use sterling, but said he had three plan Bs – a currency fixed to the pound, unilateral use of sterling or its own currency.
The move is right, said Walter Dellinger, who led the Justice Department's Office of Legal Counsel in the Clinton administration, because the proposed attack is not "covered by any of the previous precedents for the unilateral use of executive power".
His remarks are ambiguous: one can read them as both a statement of the obvious, or a clear hint that the Scottish government is subtly shifting its ground, to adopt a strategy derided by critics as "the Panama plan" after the central American country's unilateral use of the US dollar.
