Ben Rhodes, the former national security aide to President Barack Obama who helped negotiate the Iran nuclear deal, expressed concern on Thursday evening at news that the U.S. killed Iranian terror general Qassem Soleimani.

Soleimani led the Iranian Revolutionary Guard Corps (IRGC) Quds Force. In that capacity, he was responsible for the deaths of hundreds of U.S. soldiers in Iraq, and directed Iran’s foreign military adventures, including terrorism. He was killed at the airport in Baghdad, Iraq, early Friday local time, after reportedly arriving in the country late last year to repress anti-Iranian protests. The attack came days after an Iranian-backed militia attacked the U.S. embassy.

The U.S. Department of Defense later confirmed that Soleimani had been killed at President Trump’s “direction.”

Rhodes took to Twitter to warn that the death of Soleimani was “a frightening moment” that could lead to war:

Agree – no question that Soleimani has a lot of blood on his hands. But this is a really frightening moment. Iran will respond and likely in various places. Thinking of all US personnel in the region right now. https://t.co/WL0QGfRHtz — Ben Rhodes (@brhodes) January 3, 2020

Rhodes also worried about congressional authorization for Trump’s decision — though he had expressed no such concern when President Obama led the U.S. into a controversial war against Mummer Ghadafi in Libya in 2011:

Trump may have just started a war with no congressional debate. I really hope the worst case scenario doesn’t happen but everything about this situation suggests serious escalation to come. — Ben Rhodes (@brhodes) January 3, 2020

Congress has to assert itself and determine exactly what our Iran policy is. Did we mean to do this? Do we have any plan for what comes next? What is the legal basis for all this? — Ben Rhodes (@brhodes) January 3, 2020

Rhodes then added that he was specifically worried about President Trump’s “strategy” and competence to lead:

There are real world consequences to having Trump as President. They are becoming increasingly clear and he is the one who is going to have to navigate incredibly complicated and dangerous messes of his own creation. This is not reality TV. — Ben Rhodes (@brhodes) January 3, 2020

Iraq and Lebanon are just two of the places where we have to be very concerned about the potential Iranian response which could play out over time – not to mention Iran's nuclear program. Again, QS was as bad a guy as there was, but what is the strategy here? — Ben Rhodes (@brhodes) January 3, 2020

What is the strategy? We have no explanation about what happens now and what we are trying to achieve in a very serious international crisis. https://t.co/eCvn1yCXxc — Ben Rhodes (@brhodes) January 3, 2020

Under the Iran deal, the Obama administration gave Iran access to $100-$150 billion in frozen assets, as well as nearly $2 billion in cash (delivered by cargo plane), some of which is thought to have funded Soleimani’s activities.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He earned an A.B. in Social Studies and Environmental Science and Public Policy from Harvard College, and a J.D. from Harvard Law School. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.