Trump's remark that he would have treated Iran differently if it had nuclear weapons is being read as an accidental argument for other countries to rush and build them.

• Trump said that if Iran already had a nuclear weapon, he would be politely negotiating with its leader instead of bombing the country.
• The obvious lesson for other governments is that nukes buy protection from US attack.
• North Korea is the proof: it built a nuclear arsenal and got love letters and summits instead of strikes.
• The pattern critics point to is that Washington attacks countries near Israel that lack a deterrent, while leaving nuclear-armed states alone.
• The Iran war has come with a huge price tag, a closed Strait of Hormuz, and higher gas prices.

Outlook: Expect more countries to see nuclear weapons as the cheapest insurance policy against US military action.