Assuming that &quot;federalism&quot; means what I think it means (federation of independent entities, delegating economy-of-scale responsibilities like war and diplomacy to the center while keeping everything else for themselves), my guess would be this: that it ensures that government operates on a local level, where the number of people represented by a given legislature is smaller -- so individual votes have more impact and the proportion of voters frozen out by being in minorities is smaller.<p>This has two obvious failure modes: it can decay into warlordism, and the member communities can hate each other passionately enough to go to war. (So federalism is a non-starter for the US at the present day.)<p>Of course, if the poster here didn&#x27;t mean by federalism what I guessed that it means, the above is irrelevant.