'Psychologically unstable’: Renowned economist explains why Trump poses a risk to global security

The global political environment is the most dangerous it’s been in decades — and experts say President Donald Trump is largely to blame.

The consultancy firm Eurasia Group issued a troubling analysis of the current situation, which they found was nearly as unstable as during World War II, and founder Ian Bremmer discussed his findings on MSNBC's "Morning Joe" with Columbia University professor Jeffrey Sachs.

"We have a presidential system with an absolutely unfit and impulsive president," said Sachs, a professor of sustainable development and health policy. "We don't have policy right now, we are lurching day to day. Trump is unstable psychologically, the pressures are rising and he's even more unstable."

Sachs said the U.S. essentially had given up on foreign or domestic policy to reflect the moods of the president.

"What we call policy is not policy," he said. "It's being made up by the hour, where we have troops, where we have huge dangers of conflict in Syria. It's obviously being made up day by day."

"You think Trump and the wall, which is weird," Sachs continued. "He probably believes what he's saying because he's got these paranoid ideations that are all over the place, and he thinks probably that there's this massive terrorist assault coming from the southern border. I believe he believes this."

Sachs said Trump was even more dangerous after decades of executive branch growth.

"We have a presidential system which unwisely gave a tremendous amount of power to the president, especially in foreign policy, over the last 50 years," Sachs said. "Now we're living the dangers of this, and I think most people, not in his narrow base, understand that this man is psychologically unstable. But politically it's frozen right now and it's very, very dangerous."