In The Federalist Papers #3, John Jay argues that, united, the states are less likely to start or give just cause for a war. (See The Federalist Papers #3: United, the 13 States are Less Likely to Stumble into War.) In The Federalist Papers #4, John Jay argues that, united, the states will be better able to fend off unjust aggression. The first half argues that unjust aggression is a genuine danger:

“… it need not be observed that there are PRETENDED as well as just causes of war. … nations in general will make war whenever they have a prospect of getting anything by it; …”

The relevance of this observation is backed up by these arguments:

1. Monarchs can have narrowly selfish reasons to start a war.

2. Nations can be tempted to use a war to gain advantage in a commercial rivalry. For example:

   • Fishing

   • Shipping

3. Nations may view the preservation of monopolies and exclusive commercial rights as a matter of national interest and may not see the justice of the freer trade American merchants would like. For example,

   • Trade with India and China

   • Trade along the Mississippi River

   • Trade with Canada

Here is how John Jay makes this argument in detail:

|| Federalist No. 4 || 

The Same Subject Continued: Concerning Dangers From Foreign Force and Influence
For the Independent Journal.

Author: John Jay

To the People of the State of New York:

MY LAST paper assigned several reasons why the safety of the people would be best secured by union against the danger it may be exposed to by JUST causes of war given to other nations; and those reasons show that such causes would not only be more rarely given, but would also be more easily accommodated, by a national government than either by the State governments or the proposed little confederacies.

But the safety of the people of America against dangers from FOREIGN force depends not only on their forbearing to give JUST causes of war to other nations, but also on their placing and continuing themselves in such a situation as not to INVITE hostility or insult; for it need not be observed that there are PRETENDED as well as just causes of war.

It is too true, however disgraceful it may be to human nature, that nations in general will make war whenever they have a prospect of getting anything by it; nay, absolute monarchs will often make war when their nations are to get nothing by it, but for the purposes and objects merely personal, such as thirst for military glory, revenge for personal affronts, ambition, or private compacts to aggrandize or support their particular families or partisans. These and a variety of other motives, which affect only the mind of the sovereign, often lead him to engage in wars not sanctified by justice or the voice and interests of his people. But, independent of these inducements to war, which are more prevalent in absolute monarchies, but which well deserve our attention, there are others which affect nations as often as kings; and some of them will on examination be found to grow out of our relative situation and circumstances.

With France and with Britain we are rivals in the fisheries, and can supply their markets cheaper than they can themselves, notwithstanding any efforts to prevent it by bounties on their own or duties on foreign fish.

With them and with most other European nations we are rivals in navigation and the carrying trade; and we shall deceive ourselves if we suppose that any of them will rejoice to see it flourish; for, as our carrying trade cannot increase without in some degree diminishing theirs, it is more their interest, and will be more their policy, to restrain than to promote it.

In the trade to China and India, we interfere with more than one nation, inasmuch as it enables us to partake in advantages which they had in a manner monopolized, and as we thereby supply ourselves with commodities which we used to purchase from them.

The extension of our own commerce in our own vessels cannot give pleasure to any nations who possess territories on or near this continent, because the cheapness and excellence of our productions, added to the circumstance of vicinity, and the enterprise and address of our merchants and navigators, will give us a greater share in the advantages which those territories afford, than consists with the wishes or policy of their respective sovereigns.

Spain thinks it convenient to shut the Mississippi against us on the one side, and Britain excludes us from the Saint Lawrence on the other; nor will either of them permit the other waters which are between them and us to become the means of mutual intercourse and traffic.

From these and such like considerations, which might, if consistent with prudence, be more amplified and detailed, it is easy to see that jealousies and uneasinesses may gradually slide into the minds and cabinets of other nations, and that we are not to expect that they should regard our advancement in union, in power and consequence by land and by sea, with an eye of indifference and composure.

Here are links to my other posts on The Federalist Papers so far:

• The Federalist Papers #1: Alexander Hamilton's Plea for Reasoned Debate

• The Federalist Papers #2 A: John Jay on the Idea of America

• The Federalist Papers #2 B: You Trusted the Continental Congress; Trust the Constitutional Convention

• The Federalist Papers #3: United, the 13 States are Less Likely to Stumble into War