What would Lincoln do?

As the person who led the US through its most dangerous conflict, perhaps we should heed his insights. Andrew Sullivan cites this letter written by Abraham Lincoln on the wisdom of giving the President authority to wage preventative war:

"Allow the President to invade a neighboring nation whenever he shall deem it necessary to repel an invasion, and you allow him to do so whenever he may choose to say he deems it necessary for such purpose, and you allow him to make war at pleasure. Study to see if you can fix any limit to his power in this respect, after having given him so much as you propose. If to-day he should choose to say he thinks it necessary to invade Canada to prevent the British from invading us, how could you stop him? You may say to him, — 'I see no probability of the British invading us;' but he will say to you, 'Be silent: I see it, if you don't."

That's probably too long a paragraph for Incurious George to read, perhaps some one could give him a summary?

[h/t to Howard Kurtz]