WATCH: Two Trump experts walk through the president's history of being a bad deal maker

On Monday, a former executive of The Trump Organization Barbara Res and President Donald Trump biographer Michael D'Antonio explained to CNN's Anderson Cooper that the president has always lacked solid deal-making skills.

With a month into the government shutdown, the president has failed to get Congress to approve billions in funding for his border wall. Negotiations remain in a stalemate making this the longest shut down in history.

"Is Donald Trump a master negotiator?" Cooper asked.

"He is used to getting his way and is demanding. But he's never been any kind of a collaborator. He's never worked with other people," Res said. "He was a one-man show."

She said that Trump is allowing his "ego" to get in the way of working with Democrats to end the shutdown and that he thinks it's all about him.

"Was President Trump actually a great deal maker when he was a businessman or was that more public relations than reality?" Cooper then asked D'Antonio.

He explained that Trump is a "salesman" and has sold the world a false reputation of who he really is.

"He built his reputation on him selling himself and this 'deal making' thing is a part of that and he has sold himself to people. In looking back at it, well, some deals were good but most of them were not so good," D'Antonio said.

Watch below via CNN.