The Strait of Hormuz carries about one-third of all traded oil globally. When a war blocks it, every gas station sees prices from 2008.

Oil just approached $120 a barrel for the first time in 18 years.

The Math Behind the Pump

One year ago, oil was $73.78 per barrel. Today it's $112.42 - a 52% jump.

The war made traders rebuild risk into every barrel and lengthen every cargo route around Africa. Insurance costs alone are adding dollars per barrel that didn't exist six months ago.

Why Prices Stay Sticky

Gas prices don't fall as quickly as they rise. A 10% jump in crude shows up at the pump within weeks. A 10% drop takes months to appear.

The question isn't whether gas hits $4 per gallon - it probably will. The question is what comes next.

The Safety Valve

The US government keeps millions of barrels in underground storage tanks specifically for moments like this. If prices keep climbing, expect that reserve to open up.

It won't solve the problem - nothing can until the Strait reopens - but it could buy time and knock a few cents off each gallon.

What to Watch

Track three things. Shipping routes - any sign the Strait is reopening matters more than any other economic data. Strategic Petroleum Reserve releases - prices should level off within weeks if it opens. Corporate earnings calls - when companies mention energy costs as a problem, the war is showing up in portfolios.