While we don’t know the substance of what was discussed, Musk’s presence is a concerning preview of Trump’s often reckless approach to diplomacy — as well as his disregard for the line between private interests and public policy. There are a lot of reasons why Musk should be the last person hopping on that call.

Elon Musk joined Donald Trump's phone call with Ukrainian President Volodymyr Zelenskyy on Wednesday, multiple sources with direct knowledge of the call told ABC News.