What does Lincoln mean when he says ""the laws of the Union be faithfully executed in all the States?""

Lincoln means that, since he considered the constitution and the law of United States of America to be superior above any state, then, to his ability, he would defend the constitution upon which the country is binded (that is, unify the States together).

This is to ensure that America was never disintegrated into smaller countries.

Explanation:

which statement explains one of the reasons world war 1 was so much more destructive than earlier conflicts