WATCH: What's Driving U.S. Sanctions On Iran

For 40 years, the U.S. and Iran have been locked in an almost nonstop confrontation. In the latest escalation, the U.S. is demanding that other countries stop buying Iranian oil — the one product that keeps that country's economy afloat, if just barely.

These sanctions will further weaken Iran's already fragile economy and add to tensions in the region, but to what end?

To learn more, watch the video above.