Vice President Joe Biden mocked Donald Trump this week for suggesting that the coalition fighting the Islamic State of Iraq and Syria is invading Mosul to help Hillary Clinton politically.

“Donald Trump…He’s convinced that the reason they’re moving in Mosul now is to make Hillary Clinton look tough,” Biden said in an interview with Face the Nation moderator John Dickerson that will air Sunday. “Can you believe somebody’d say that? It’s like Eisenhower saying, ‘We’re going to Normandy.’ And you say, ‘Well, that’s done to help the reelection of the president of the United States of America.’”

“Come on, man,” Biden continued. “This guy’s not fit to be the commander-in-chief.”

The vice president also rebuffed Trump’s argument that military planners should not have telegraphed the coalition’s plan to invade Mosul, the heart of ISIS in Iraq.

Trump has claimed he’s “smarter than the generals” and described coalition military planners as a “bunch of amateurs” for announcing plans to liberate Mosul.

“Why say you’re going into Mosul?” asked Dickerson. “Why telegraph it?”

“We have been making it clear that we’re going to go into Mosul as a coalition for the better part of the last two years, because we’re putting together the rationale for a coalition to move in and take away the caliphate,” Biden explained. “That’s the same reason why we just announced that the Secretary of Defense said we’re going to go to Raqqa, which is the other element of the caliphate.”

The announcement, Biden added, makes it “clear to our friends and allies and the Arabs who are not part of – which is the vast majority, overwhelming majority – are not part of ISIL, ‘We’re not leaving you. Hang on. We’re going to come.’...So there’s a lot of reasons for it.”

Tune in Sunday for more of our interview with Vice President Biden. Check your local listings for airtimes.