The former chief of staff explained, in the clearest terms yet, his misgivings about Trump’s behavior regarding North Korea, immigration, and Ukraine.

MORRISTOWN, N.J.—Lieutenant Colonel Alexander Vindman, the former National Security Council aide and impeachment witness President Donald Trump fired Friday, was just doing his job, former White House Chief of Staff John Kelly told students and guests at a Drew University event here Wednesday night.

Over a 75-minute speech and Q&A session, Kelly laid out, in the clearest terms yet, his misgivings about Trump’s words and actions regarding North Korea, illegal immigration, military discipline, Ukraine, and the news media.

Kelly, a retired Marine Corps general, said that Vindman is blameless and was simply followed the training he’d received as a soldier; migrants are “overwhelmingly good people” and “not all rapists”; and Trump’s decision to condition military aid to Ukraine on an investigation into his political rival Joe Biden upended long-standing U.S. policy.

Vindman was rightly disturbed by Trump’s phone call to Ukrainian President Volodymyr Zelensky in July, Kelly suggested: Having seen something “questionable,” Vindman properly notified his superiors, Kelly said. Vindman, who specialized in Ukraine policy at the National Security Council at the time, was among multiple U.S. officials who listened in on the call. When subpoenaed by Congress in the House impeachment hearings, Vindman complied and told the truth, Kelly said.

“He did exactly what we teach them to do from cradle to grave,” Kelly told the audience at the Mayo Performing Arts Center. “He went and told his boss what he just heard.”

Although Trump has long insisted that his call to Zelensky was “perfect,” Kelly made clear that Trump indeed conditioned military aid on Zelensky’s help digging up dirt on Democratic presidential candidate Joe Biden.