Iran is now warning European countries that host US bases used against it, and Bulgaria is the first target — a dangerous widening of the war.

• Iran says any base anywhere used to attack Iranians is fair game, and it has already hit bases in Kuwait, other Gulf states, and Jordan.
• Bulgaria drew the threat after its parliament voted to let the US use bases there for the war.
• Iran brushes off the NATO angle: the US is already NATO's biggest member and Iran is already fighting it, so Bulgaria changes nothing in their eyes.
• Israeli and US strikes killed many senior Iranian leaders, and their replacements are more radical and more willing to take risks.
• Iran's earlier responses were deliberately restrained to avoid casualties; that restraint is gone.

Outlook: The threat looks credible rather than a bluff, and any European country that lends its bases risks being pulled directly into the fighting.