Oil could spike toward $100 a barrel as the US squeezes Iran's oil exports, a move that's really aimed at slowing China down.

• Iran exports a lot of cheap oil to China, so hurting Iran's oil sales also hurts China's economy.
• The Strait of Hormuz, a narrow shipping lane that carries about a quarter of the world's oil, is at the center of the squeeze.
• Any disruption there has already pushed oil prices up, and a prolonged closure could send prices toward $100 a barrel or higher.
• This fits a bigger US strategy of cutting China off from cheap resources, following similar moves against cheap oil from Venezuela and cheap silver from Latin America.
• Making China more dependent on US-aligned energy sources gives Washington more leverage over Beijing.

Outlook: If tensions around the Strait of Hormuz keep escalating, expect oil prices to keep climbing and US-China economic tension to deepen.