Typical 3rd world militaries are meant to look good rather than be good. Buying target drones is an indicator they are preparing to fight because they hardly ever, if ever, do so now. Their purchase of drones large enough to carry nuclear warheads would be an intelligence tipoff to the US, especially if those are not expended in practice. That is a major question for potential adversaries given the human and electronic surveillance systems that the drug trade and illegal immigration have spawned along the American coasts. Then there is the nuclear control issue.
Terrorism presents different problems.
This would be lethal to a small state like Israel, but not to the US because of its vast geographic size. It would only terminally infuriate the American people if used on us. Missile defenses cannot stop terrorism any more than they can stop abortion or the common cold. People saying that they cannot, therefore missile defenses are useless, are not to be taken seriously. Any SDI system would rely on satellites for launch detection and target tracking.