National Security Adviser John Bolton will warn the Iranian regime that there will be "hell to pay" if they "continue to lie, cheat and deceive" or "cross" the U.S. and its allies, according to excerpts of the speech he's set to give later this afternoon.

Why it matters: Bolton’s speech, in which he’ll also declare the Iran deal "the worst diplomatic debacle in American history," contains some of the most aggressive and confrontational language we've seen from a U.S. administration in recent decades. Bolton has argued for military intervention in Iran in the past, and he warns in this speech: "We are watching, and we will come after you."

Between the lines: The contrast with America's European allies could not be greater. This aggressive speech comes just a day after the Europeans doubled down on their commitment to the Iran nuclear deal by announcing they would set up a special payment channel to allow European companies to keep dealing with Iran while ducking U.S. sanctions.

Per the WSJ: "EU foreign-policy chief Federica Mogherini and Iran’s Foreign Minister Javad Zarif made the announcement of a 'special purpose vehicle' jointly, in English and Farsi, after a meeting at the U.N. of the parties still committed to the deal — Iran, EU, U.K., France, Germany, Russia and China."