Speaking at a forum on emergency food aid, Corker, who is set to retire in 14 months, also pointed to Cabinet officials who, he said, "represent interests," and decried what he sees as an appalling lack of fiscal discipline.
"The White House is made up of a large number of people," Corker said at the American Enterprise Institute. "There are people that have a lot of negativist instincts that exist there, that are contrary to some more prudent norms."
Corker, the seasoned and smooth chairman of the Senate foreign relations committee, has taken off the gloves in recent weeks, speaking about Trump's behavior as irresponsible and dangerous with a candor
that has left many in Washington blinking in surprise.
He told The New York Times that Trump is setting the US "on the path to World War III," and running the presidency as if it were a reality TV show. He added that, "he concerns me, he would have to concern anyone who cares about our nation."
On Thursday, it was clear he isn't ready to stand down. An audience member told the former Chattanooga mayor he wanted to ask a question that his roommate had raised: Should there be a competency test for the presidency?
The moderator jumped in to interrupt, saying, "we're not going to go there right now!"
"I'm glad to go there," Corker said, to audience laughter.
The moderator pleaded, "but this is about food aid ..."
Corker, chuckling, gave in to the moderator's request, telling his questioner to, "thank your roommate for his question, I understand his or her sentiments."
But a few minutes later, politics intruded again when Corker was asked about food aid. The senator, who also focuses on anti-slavery issues, is pushing for changes to the way emergency food aid is distributed.
The current system benefits American businesses, but is deeply inefficient and badly undermines farmers in developing countries. Corker described it Thursday as "absolute stupidity." He pointed, in part, to entrenched interests in Congress, in the form of staffers who work on the "farm bill," which is being renegotiated this year and sets five years of eating and farming policy in the United States.
Corker was asked about reports that he'd intervened in June when Trump was considering an executive order that would require 100% of food aid, up from 50%, to be transported on US-flagged vessels. The requirement mostly benefits two New York companies, Corker said, and can mean that aid takes months to reach starving people.
Corker credited the President for understanding the issue and deciding not to go forward with the executive order, but he said the battle wasn't over. He pointed to "forces" within the White House.
His call to the President "stopped it at that moment, but these forces within will continue and so, you know, we've got to continue to use reason," Corker said.
"We are our greatest threat to ourselves"
"There are actually, unfortunately, Cabinet secretaries that represent interests," he said, and who hold a "political standpoint to make, unfortunately, a small group of people happy that might have supported the President, which is again unfortunate."
"They're going to continue to push this type of activity," Corker said. "So again, it stopped currently, but it's not something that, you know, it's going to continue on, and we've got to do everything we can to keep that from raising its head again."
Corker also touched on the administration's taxation and spending proposals, saying that, "we're at a moment in time where I'm seeing the least discipline since I've been here."
"I don't know what's happened since the election in November," Corker said.
Addressing the audience directly, Corker noted that there were many young people present.
"We are our greatest threat to ourselves," Corker said. "The greatest threat to you and your life and your freedom is us, our inability to control our finances ... It will be our downfall, it will cause us to be less generous around the world."