President Donald Trump has long been posturing toward military action in Iran — but one of his top generals pumped the brakes on the whole thing, enraging him, Slate reported on Tuesday."The military warning — first reported in the Washington Post, then confirmed in the New York Times — must be particularly rankling," wrote Fred Kaplan. "According to the reports, in a recent White House meeting with many top officials present, Gen. Dan Caine — whom Trump selected, and has since highly lauded, as chair of the Joint Chiefs of Staff — said that a shortage of munitions and the absence of any allies would make a prolonged war with Iran very difficult.""It is unusual for Trump’s advisers to dampen his fantasies of easy wins, and it is less common still for high-level discussions of military plans to be leaked," the report continued. "The fact that Caine confronted Trump on this plan, and that someone spilled this to the public, suggests a growing concern among some inside players that the president’s increasingly casual adventurism could engulf the armed forces, the region, and the nation in danger."Trump, for his part, has said that Caine “has not spoken of not doing Iran” in response to the article — but, Kaplan notes, the original reports never actually said Caine told Trump not to attack Iran, but simply explained why it would be extremely difficult.Caine, for his part, did oversee the Trump administration's strike on Iran's nuclear facilities last year, which, while controversial, did not come at a great cost to the United States.However, said the report, "Operation Midnight Hammer, as the attack was known, was a speedy one-off venture where three B-2 bombers dropped bunker-busting bombs, watched them hit their targets, and sped back home, the end ... A larger attack on Iran — whether to wipe out more of its nuclear infrastructure, destroy its ballistic-missile fleet, or overthrow the regime — would be a much more elaborate, time-consuming business."