If the power did not exist, then the violation of the Constitution would be an effective argument against such an undertaking.
Whatever the conclusion might be, therefore, as to the legality of the guaranty or as to whether the obligation was legal or moral in nature, it did not seem possible for it to escape criticism and vigorous attack in America.
It seemed to me that the President's guaranty was so vulnerable from every angle that to insist upon it would endanger the acceptance of any treaty negotiated if the Covenant was, in accordance with the President's plan, made an integral part of it.

Then, too, opposition would, in my opinion, develop on the ground that the guaranty would permit European Powers to participate, if they could not act independently, in the forcible settlement of international quarrels in the Western Hemisphere whenever there was an actual invasion of territory or violation of sovereignty, while conversely the United States would be morally, if not legally, bound to take part in coercive measures in composing European differences under similar conditions.

It could be urged with much force that the Monroe Doctrine in the one case and the Washington policy of avoiding "entangling alliances" in the other would be so affected that they would both have to be substantially abandoned or else rewritten.

If the American people were convinced that this would be the consequence of accepting the affirmative guaranty, it meant its rejection.

In any event it was bound to produce an acrimonious controversy.