Trump is publicly threatening Oman over a possible shipping deal with Iran, a bad sign for oil markets and for US allies in the Gulf.

• Oman has been working with Iran on a route through the Strait of Hormuz that would send more ships past the Omani coast.
• The two countries would split the fees, but the deal is expected to shut out US ships and ships from countries helping the US.
• Trump said on Fox News that Oman will get bombed if it interferes.
• The deal would actually get more oil moving, so blocking it cuts against lower energy prices.
• The threat lands on a longtime ally, a warning to other partners that stepping outside the US playbook carries a cost.

Outlook: Expect more pressure on Oman and jumpy oil markets while the Hormuz route stays unresolved.