Wrong. Defense done right (which includes power and competence in spades) deters aggressors. This does not include stupid shit like destabilizing Syria a la Hillarity (which had virtually nothing to do with defense spending -- that and others were geo-political mistakes.)
TODAY, we are at near historical lows since WW2 in defense spending as a % of GDP, but unlike the Bill Clinton years, we have much more formidable foes to face. Those enemies see our weakness and are acting as would be expected.