One possible solution is to intentionally introduce Ancient Rome's "Brittania Problem".

Specifically, fund a distant vassal state which requires a military so enormous to maintain peace that any general in charge of said military would pose a legitimate threat to the executive back home.

Enforcement could, then, simply be accomplished by Congress, et al. incentivizing said general to stage his coup.

Now that I think of it... this could be one practical way to accomplish something akin to Trotsky's "Permanent Revolution".