The US military looks weaker than people assumed, which is bad news for American power and global shipping.

• A key narrow waterway for global shipping and commodities has been blocked for months.
• Despite huge spending on aircraft carriers, the US has not been able to reopen it.
• Iran is small, poor, and often mocked, yet the US could not force it to back down.
• The lesson: stating goals out loud does not make them happen, even with the world's biggest military.

Outlook: Expect more doubts about US military strength and continued pressure on global shipping and commodity prices if the strait stays closed.