Each citizen, Smith, ruled by any state S should demand as a matter of ideology unconditional foreign policy pacifism on the part of S. There shall be, he should insist, no standing military forces of any kind, nor should the state defend itself against any foreign aggression.
Let now some state T led by ruthless dictator Jones invade, decapitate the S's chief, install Jones as ruler, and bring foreign mercenaries as the new military.
No "defense" should be attempted. Still less ought Smith to be conscripted by S to defend S and the existing ruler. S's price of power is precisely its vulnerability to be conquered.
Instead, Smith, when things settle down, and T gets down to the daily grind of governing, even if perhaps with a heavier hand, should continue influencing the new government, T and Jones in particular, toward complete pacifism, disarmament, and retrenchment.