More than an hour after missiles began targeting top Iranian officials across downtown Tehran, President Trump for the first time described his goal to the American public: for the most powerful armed factions in Iran to lay down their arms and for Iranians to rise up and risk death by seizing control of their government.In an eight-minute address on Truth Social that amounted to a declaration of war, Trump also acknowledged the possibility of American casualties. Within three hours of the initial strike, Iran’s Revolutionary Guard Corps said it launched ballistic missiles at four nearby U.S. bases, and the sound of air defenses shooting down missiles reverberated across the region. Iranian forces successfully struck inside Bahrain, home to the U.S. Fifth fleet. Air defenses appeared to have shot down missiles aimed at Qatar (home to the largest U.S. military base in the region), the United Arab Emirates and Kuwait (which also host American forces) and Israel, which joined U.S. forces in the attack. Jordan, where American aircraft are parked, also said it shot down missiles. The last U.S. strikes on Iran, in June, were aimed at curtailing Iran’s nuclear ambitions. This time, Trump went much further, making clear his desire for a change in Iran's leadership for the first time in 47 years as well as for the elimination of its nuclear and ballistic-missile development programs. He is pursuing that war without congressional approval, little appetite among his base for another U.S. regime-change operation in the Middle East, and with several allies in the region having discouraged new strikes, fearing a broader conflict. That leaves Trump in a position to claim personal credit for any successful parts of the mission—he said “no president was willing to do what I am doing tonight”—but also singularly associated with whatever happens next in Iran and across the Middle East. He will receive the accolades for whatever goes well, but will also be saddled with the many possible downsides, from U.S. and civilian casualties to the instability that could be unleashed if the Iranian regime falls in the face of the American and Israeli onslaught.U.S. and Israel called the operation "preemptive." Trump said Iran was developing missiles that could reach the U.S. even though intelligence assessments within his administration have not reached that same conclusion. He said Iran posed an imminent threat, but had also said last June that U.S. and Israeli forces crippled Iran’s nuclear-development program. Trump did not say when or what would lead the U.S. to stop its campaign.Instead, he outlined how the regime has posed a threat for the past four decades, saying the Saturday attack was designed to ensure that Americans will never be “threatened by a nuclear-armed Iran.” Trump also referenced nationwide protests across Iran that began December 28, which he had previously promised to support.But the most startling-–and unexpected-–declaration was his ambition to oust the Iranian government. Trump offered immunity to members of the Iranian Revolutionary Guard Corps, the armed services, and the police, if they laid down their arms. The alternative, he said, was “certain death.” Yet he didn’t say who any takers should surrender to, given the operation has not involved any ground forces. And he put the onus of revolution onto Iranians themselves, saying the strikes were designed to create the people’s best chance for new leaders for generations. But he remained vague about who among Iran’s various opposition who he expected to rise up. He urged Iranians to shelter in place until the bombing abated, then had pointed advice for what they should do next: “When we are finished, take over your government.”What Trump described as a “noble” mission has been anticipated for weeks, even while the U.S. and Iran were engaged in indirect talks over curtailing Iran’s nuclear ambitions, with Oman mediating. The last round of talks was Thursday in Geneva, which Oman’s foreign minister said had led to tangible progress, and technical talks were scheduled to take place Monday in Vienna. Trump made clear his frustrations over what he viewed as Iranian intransigence in the negotiations. While Iran had the chance of an off-ramp from the threat of strikes if it offered some concessions, U.S. officials said, they also early this week privately hinted at the imminence of military action.Israeli officials were first to announce the war, and said they were working hand-in-hand with the U.S. The Pentagon called the mission “Operation Epic Fury.”“Our joint action will create the conditions for the brave Iranian people to take their destiny into their own hands,” Israeli Prime Minister Benjamin Netanyahu said in a statement. The strikes appeared to be targeting Iranian leaders first, to set the stage for going after Iran’s defenses.[Read: Trump’s enormous gamble on regime change in Iran ]By 10 a.m. local time, explosions erupted across downtown Tehran, near government buildings, including near Supreme Leader Ayatollah Ali Khamenei’s compound. According to local reports, explosions were heard near the cities of Isfahan, Qom, Karaj, and Kermanshah. U.S. military ordnance arrived by both air and sea, officials told us. They said the U.S. attack would be more extensive than the June strikes on three Iranian nuclear facilities.The strikes were welcomed by Iranians so fed up with the regime that they took to the streets in unprecedented numbers late last year and early this one. Many believed that their push for regime change could not happen with protests alone. The Iranian government crushed the movement with merciless force, with estimates of tens of thousands dead. Despite the lethal risks protestors face, Trump—standing against a black backdrop at Mar-a-Lago while wearing a white USA hat and no tie in his early-morning address—urged the people to seize control. Left unclear was how that might happen. The regime, which has been entrenched since the 1979 revolution that overthrew the Shah, controls every lever of government and national security. Before the war, experts had said that if the regime fell, it could as easily be replaced by the Islamic Revolutionary Guard Corps or other government factions as by democracy-minded Iranian civilians.Yet in the run-up to Saturday’s strikes, Trump told aides that he believed toppling the regime in Tehran could be his crowning foreign policy achievement, allowing him to realize a goal that eluded his predecessors. There were no immediate confirmed deaths in Israel or among U.S. troops. The UAE said a civilian died as its military shot down missiles, according to the state news agency. And while it appeared Iran’s top leaders survived the initial assault, several lower level IRGC commanders were allegedly killed.In the run-up to Saturday's attack, the U.S. sent more than 150 military aircraft and drones towards the region, drawing forces from elsewhere in the world. Satellite photos show aircraft positioned on runways across Europe, in Jordan, and on aircraft carriers. The extraordinary accumulation of firepower came from across the globe. The USS Abraham Lincoln carrier strike group left its mission in the Pacific. The USS Gerald R. Ford aircraft carrier and its accompanying ships left the Caribbean Sea and are now in the eastern Mediterranean Sea. And the U.S. deployed nearly 20 destroyers and submarines. Conservatively, the Pentagon already has spent hundreds of millions of dollars for the largest buildup of U.S. military sea and air assets since its 2003 invasion of Iraq.[Read: What Trump fails to grasp about Iran]Over his two terms, Trump has developed a taste for flexing U.S. military muscle, with strikes over the past year in Iran, Venezuela, Syria, Somalia, Nigeria, and on alleged drug boats in the Caribbean. He appears to have concluded that as long as U.S. military intervention doesn’t involve thousands of ground troops or protracted strikes over years, it can be politically beneficial and send a message of military might to China and Russia.The January 3 special-forces raid on Caracas that captured Venezuelan President Nicolás Maduro, which came after a similar military build-up off Venezuela’s coast, gave Trump further confidence that he could tackle America’s long-standing foreign-policy problems. Yet what he is proposing for Iran goes far beyond anything he has previously countenanced.“Iran is ready for a generational event that is going to decide the future of the country,” Vali Nasr, a professor of international affairs and Middle East studies at the Johns Hopkins School of Advanced International Studies, told us. “The U.S. is not ready psychologically for anything that is more than a 24 hour news cycle.”Iran’s response to the attack may expand beyond the ballistic missiles it has used in the past to retaliate. Iran’s navy—which Trump also vowed to destroy—conducted an exercise in the Strait of Hormuz earlier this year, which appeared intended to signal that it has the ability to shock global markets. Iran could also send drones, like the one that flew near the USS Abraham Lincoln carrier strike group earlier this year, and try to damage nearby U.S. warships. And it could deploy its proxies across the region to target U.S. bases. But Iran is already much diminished from what it had once been. The country’s economy is moribund. And U.S. and Israeli targeting of its leadership could make it harder for Iran’s military to coordinate its response. U.S. and Israeli strikes last year struck Iranian air defenses and ballistic-missiles capabilities, which could curtail the regime’s ability to retaliate or defend against missiles and fighter jets entering the country.Few in Trump’s small inner circle wanted a full-fledged war, officials told us, with Vice President J.D. Vance, who often displays the most isolationist tendencies, sounding caution. Air Force General Dan Caine, chairman of the Joint Chiefs of Staff, warned of potential U.S. casualties and of dwindling munitions, particularly of air defense missiles. But Trump, more than most presidents, has made foreign affairs a test of personal relationships, and is often preoccupied with avoiding looking weak. Republicans who have spoken to the president and his inner circle in recent days believed that a diplomatic deal would have needed to be a clear win in order for Trump to feel comfortable pulling back the massive force he had summoned. Saturday’s action made all those considerations moot. Nowhere in his eight-minute speech did Trump offer any prospect of renewing negotiations, instead referring to the regime as “a vicious group of very hard, terrible people.”During both of his presidential campaigns, Trump reassured his supporters there would be no more “forever wars,” and that the U.S. wouldn’t be bogged down in the Middle East. But with the launch of Saturday’s airstrikes, the U.S. is once again on the frontlines of conflict there, with the desire to overthrow a nation’s government. How long war lasts—and where it leads Iran—is not up to just Trump or Israel. The fate of a war Trump sees as shaping his legacy is now in the hands of both the regime and the people inside Iran.**Illustration Sources: Archive Photos / Getty; John Moore / Getty; Saul Loeb / AFP / Getty; Nathan Howard / Getty; Morteza Nikoubazl / NurPhoto / Getty.