The provision of the Constitution giving the war-making power to Congress, was dictated, as I understand it, by the following reasons. Kings had always been involving and impoverishing their people in wars, pretending generally, if not always, that the good of the people was the object. This, our Convention understood to be the most oppressive of all Kingly oppressions; and they resolved to so frame the Constitution that no one man should hold the power of bringing this oppression upon us. But your view destroys the whole matter, and places our President where kings have always stood.

Abraham Lincoln (1809-1865) American lawyer, politician, US President (1861-65)

Letter (1848-02-15) to William H. Herndon
    (Source)

Lincoln understood Herndon to be proposing that the President, on their own initiative and judgment, was entitled to preemptively invade another country to repel an anticipated invasion. Herndon felt this principle justified Polk's sending of troops into disputed territory, which led to the Mexican-American War (1846-1848), though Polk didn't justify his actions in that way.