Federalist Papers 3E

Because, even if the governing party in a State should be disposed to resist such temptations, yet as such temptations may, and commonly do, result from circumstances peculiar to the State, and may affect a great number of the inhabitants, the governing party may not always be able, if willing, to prevent the injustice meditated, or to punish the aggressors. But the national government, not being affected by those local circumstances, will neither be induced to commit the wrong themselves, nor want power or inclination to prevent or punish its commission by others.

So far, therefore, as either designed or accidental violations of treaties and the laws of nations afford JUST causes of war, they are less to be apprehended under one general government than under several lesser ones, and in that respect the former most favors the SAFETY of the people.

As to those just causes of war which proceed from direct and unlawful violence, it appears equally clear to me that one good national government affords vastly more security against dangers of that sort than can be derived from any other quarter.

Because such violences are more frequently caused by the passions and interests of a part than of the whole; of one or two States than of the Union. Not a single Indian war has yet been occasioned by aggressions of the present federal government, feeble as it is; but there are several instances of Indian hostilities having been provoked by the improper conduct of individual States, who, either unable or unwilling to restrain or punish offenses, have given occasion to the slaughter of many innocent inhabitants.