Former CIA Director John Brennan rebuked President Donald Trump's decision to pull the United States out of the 2015 Iran nuclear deal.

Brennan, who has often criticized the president for his habit of undermining the intelligence agencies he's supposed to rely on, called the move a sign of "madness" that is "a danger to our national security" in a post on Twitter:

Today, Donald Trump simultaneously lied about the Iranian nuclear deal, undermined global confidence in US commitments, alienated our closest allies, strengthened Iranian hawks, & gave North Korea more reason to keep its nukes. This madness is a danger to our national security.

Brennan, who now works as an analyst for NBC and MSNBC, also voiced his concerns on the air.

“This is not just foolish, this is dangerous,” he said. “And Mr. Trump has repeatedly misrepresented the facts of the nuclear deal with Iran. He’s basically lied to the American people and lied to the world about what that deal entails.”

Brennan has described himself as "nonpartisan." He insists, however, that Trump is a danger to the republic who has failed to fulfill his duties as the leader of a nation now reeling from sizeable hits to its credibility.

“I think he is dishonest. He lacks integrity. He has very questionable ethics and morality. And he views the world through a prism of how it’s going to help Donald Trump,” Brennan told NPR last month. “And I just think that he has not fulfilled the responsibilities of the president of the United States office.”

Indeed, the president failed to offer solutions during yesterday's announcement that the United States would exit the landmark agreement.

“It is clear to me that we cannot prevent an Iranian nuclear bomb under the decaying and rotten structure of the current agreement,” Trump said from the White House Diplomatic Room. “The Iran deal is defective at its core. If we do nothing we know exactly what will happen.”

Trump had long campaigned against the nuclear deal and made exiting the agreement one of the signature pledges of his candidacy during the 2016 presidential election. He noted that any nation that helps Iran obtain nuclear weapons would also be “strongly sanctioned.”

“This was a horrible one-sided deal that should have never, ever been made,” the President said. “It didn’t bring calm, it didn’t bring peace, and it never will.”

The president had earlier criticized the deal as one of the Obama administration’s “worst” decisions, and in his statements, he expressed his belief that the deal served to benefit the Iranian regime while sponsoring terrorism.

“At the point when the US had maximum leverage, this disastrous deal gave this regime — and it’s a regime of great terror — many billions of dollars, some of it in actually cash — a great embarrassment to me as a citizen,” Trump said.

Brennan is far from the only political figure to condemn the president's action. In a joint statement, the leaders of the United Kingdom, France and Germany expressed "regret and concern," acknowledging they wish to sustain the agreement, which provided Iran some relief from international sanctions in exchange for limits on and guarantees of transparency about its nuclear aspirations.

European leaders had earlier tried––and failed––to convince the president to preserve the nuclear deal.

French President Emmanuel Macron met with President Trump last month and urged Congress to not only stay in the deal, but seek to improve it. German Chancellor Angela Merkel and British Foreign Secretary Boris Johnson, in separate meetings with the president, also urged him to keep the deal, agreeing with the assessment from U.S. intelligence agencies and Secretary of State Mike Pompeo that the deal limits Iran’s nuclear capabilities for now and that Iran has always complied.

Proponents of exiting the agreement have cited weaknesses that the leaders of France, Germany, and Britain themselves have acknowledged and pledged to improve. These include:

• eliminating expiration dates on vital restrictions on Iran’s nuclear activity, allowing Iran to resume large-scale processing of nuclear fuel starting in 2025
• allowing inspections of military sites, which Iran currently prohibits
• limiting Iran’s ballistic missile program
• addressing Iran’s support for terrorist groups across the Middle East

But Trump's decision, writes CNN's Stephen Collinson, "opened a new window into Trump's political soul, showing his willingness to unleash the kind of chaos abroad he has fomented at home":

The decision added context to his "America First" foreign policy doctrine and showed he is adamant about following through on campaign promises that horrified America's allies.

And it revealed two other pillars of the Trump presidency––a propensity to turn even the most crucial moments into a global televised drama, and his ravenous desire to eradicate President Barack Obama from the history books.

Speaking on the air yesterday, Marie Harf, a political commentator for Fox News who worked as the Senior Advisor of Strategic Communications to former Secretary of State John Kerry and led the Iran nuclear negotiations communications strategy, criticized the president’s move, observing that “saying it [that the United States will exit the deal] doesn’t just make it so.”

Harf noted, in particular, that the president only condemned the deal, and never offered a course of action going forward:

I thought what was interesting was that Donald Trump said a lot about what he didn’t like in the deal. He said a lot about how bad Iran’s behavior is, and he said very little about what comes next, and how he will actually work to fix the deal, whether he has a comprehensive plan in place, and he almost made an implicit military threat when he said, ‘If Iran moves in a direction we don’t want them to, they will face a problem like they’ve never seen before.’

So for a lot of us, the question facing the president today wasn’t whether or not we should have done the deal originally. We know how he feels about that. It’s what the best course is moving forward, and if tomorrow Iran kicks out the inspectors, if they restart their enrichment because now we have made the deal null and void, what will Donald Trump do? We did not hear details about how he will prevent Iran from getting a nuclear weapon going forward, and I think it’s incumbent upon him and his administration now to lay out their case for how they will do that.