The Political persuasion that a dispersion of power among constituent State Governments is preferable to a concentration of power in a central Federal Government.
CON Federates understood where Federalism would take the U.S. and every nation which placed ultimate power in central governments.
When was the last time a group of citizens in one country decided to attack a group of citizens in another country when the groups involved were not Federal Governments?
It just doesn't happen.
Only people who want to control other people in their country want to control people in other countries.
Federalism is a disease which ultimately kills its host one way or another.
'Government is best which governs least' is the truth that gets ignored by every arrogant, greedy, elitist aspiring to remake the world in their own image.