‘It is a federal crime’: Former Homeland Security chief who worked for Giuliani says Trump broke the law

President Donald Trump broke federal law by illegally soliciting foreign election assistance, a former federal prosecutor explained on MSNBC on Monday.

Anchor Katy Tur interviewed former Department of Homeland Security Secretary Jeh Johnson. Earlier in his career, Johnson served as an Assistant US Attorney prosecuting public corruption under Rudy Giuliani.

"What is the magnitude of this, Jay?" Tur asked. "Put it in perspective for us. The president calling a foreign country and talking about his political opponent in the next election."

"As you noted, I was — I am a former federal prosecutor, it should go on my banner today," he replied. "Under Rudy Giuliani, he hired me alongside Jim Comey, and I prosecuted public corruption cases."

"It is a federal crime to solicit or knowingly accept the assistance of a foreign government -- or foreigner -- in a federal election," Johnson reminded.

"That’s for starters. The second, find it extraordinary an American president would solicit a foreign government to investigate a private American citizen," he added.

Watch: