A US military operation against Iran was reportedly scaled back, and there are signs of a growing rift inside the American military — bad news for the Trump administration's Iran plans.

• A bigger US operation was moving forces into the region but got stalled.
• US ships could not reliably get through the Strait of Hormuz, a key waterway near Iran.
• Because of that, plans to land Marines on Iranian islands were seen as too risky.
• Senior military leaders are said to be breaking with the White House, saying the strategy is not working.
• There are hints of a shakeup at the top of the uniformed military command.

Outlook: Expect more friction between military commanders and the administration as the Iran push loses momentum.