This is an edition of The Atlantic Daily, a newsletter that guides you through the biggest stories of the day, helps you discover new ideas, and recommends the best in culture. Sign up for it here.This morning, as his 8 p.m Eastern deadline for Iran to open the Strait of Hormuz and make other concessions looms, President Donald Trump threatened to wipe the country out entirely.“A whole civilization will die tonight, never to be brought back again,” Trump declared on Truth Social. “I don’t want that to happen, but it probably will.” The president did express hope that “different, smarter, and less radicalized minds prevail,” which would prevent such an attack. Bizarrely, he ended with a benediction for the same people he had just threatened to slaughter: “God Bless the Great People of Iran!”Though Trump rarely speaks clearly, this threat would appear to meet the definition of genocide under the 1948 UN convention: “acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group.” The president has spent the past few days warning he would attack civilian infrastructure, which most experts agree would constitute a war crime, but an apparent explicit threat of civilizational erasure is unheard of outside of cartoon villains; even most real-world genocidaires have denied that’s what they’re doing.But Trump’s message this morning is also notable for the autocratic view that underpins it. His position is that if he wants to wipe out “a whole civilization,” then that is his decision to make—unconstrained by American law, international law, Congress, or public opinion. “Only President Trump knows what he will do, and the entire world will find out tomorrow night if bridges and electric plants are annihilated,” White House spokeswoman Anna Kelly told The Wall Street Journal.This view is legally, morally, and practically disastrous. Such action by the president is not what the framers of the Constitution laid out. They granted the power to declare war to Congress alone, as my colleague Quinta Jurecic has written: “That design choice represented a radical break from the monarchies of Europe, where kings and queens had the ability to decide when to mobilize their countries to war.” That separation of powers has gradually eroded over decades, but Trump’s war in Iran goes a step beyond what previous presidents have done. The unilateral decision to erase a civilization would go a huge step past that.Members of the military are required to refuse an illegal order, including a violation of international law, but any individual soldier, sailor, or airman is poorly equipped to assess the law—and most do not realistically feel empowered to refuse an order. When several Democratic members of Congress made a video reminding servicemembers that they can and must refuse unlawful orders, the Trump administration sought to punish them through legal and military justice processes.Although the founders could scarcely have imagined the military might the United States would one day possess, the division of powers was intended in part as a check on the ethical compass of a single individual. Trump has previously said he is bound only by his own “morality,” which is not reassuring given his track record of fraud, dishonesty, racism, and misogyny.But granting such power to a single individual is also impractical, because it prevents adversaries from negotiating effectively. Iran has given no public indication that it will make concessions, and Tehran appears emboldened and in some ways strategically stronger than when the war began. But even if the Iranian government wanted to reach an agreement, it would struggle to do so. Trump has failed to clearly articulate his aims for the war—not to the American public, not to Congress, and not to the world. His demands can’t be met because they change almost daily, and none of his advisers have obvious influence over him. During a press conference yesterday about the war, in which top officials spent much time fawning over the president, Trump declared, “I have the best plan of all, but I’m not going to tell you what my plan is.”Trump also claimed in the same press conference that Iranian civilians are eager for his attacks to continue, and while many Iranians do detest the regime, even some who welcome American intervention have pleaded for strikes on civilians to cease.Trump’s threats today were quickly denounced, not only by Democrats and progressives but also by some on the anti-war right. The conspiracy theorist Alex Jones declared that “Trump literally sounds like an unhinged super villain from a Marvel comic movie. This IS NOT WHAT WE VOTED FOR!!!” Tucker Carlson, another conspiratorial voice who is one of the most influential MAGA media figures, said that officials should refuse to grant Trump access to nuclear weapons: “It's time to say no, absolutely not, and say it directly to the president, no.”Some GOP members of Congress have also expressed discomfort with attacks on civilians, but overall, the reaction among Republican elected officials has been muted—throughout the war and especially today. But because so many people on the right have worked to consolidate Trump’s power, insulate him from repercussions for his actions, and discredit his critics, it’s not clear how much the president would care even if he did receive more criticism. He doesn’t believe anyone has the right to stand in his way.