Donald Trump would be a "nightmare" as U.S. president, making relations with other countries "extraordinarily difficult" and placing the U.S. economy in jeopardy, Joseph Stiglitz told CNBC, adding that the Republican candidate had "no deep understanding of economics other than knowing how to go bankrupt."
"We can only hope he won't bankrupt the country," Stiglitz, a Nobel-prizewinning economist, told CNBC.
Trump, a billionaire businessman, has filed for at least four bankruptcies, with NBC News putting the figure at six. He will contest Democrat candidate, Hillary Clinton, in the November U.S. presidential election.
Trump has previously said he would renegotiate the U.S. national debt as president, although he has since backtracked on this.
"That is… something that it is almost unimaginable that any leader would say … That is not the way capital markets will work," Stiglitz told CNBC.
He said a Trump presidency would pose serious problems for U.S. foreign relations, highlighting the Republican's promise to build a wall across the border with Mexico to keep illegal immigrants out.
"I think it will be extraordinarily difficult for our relations with other countries, for our economic relations with other countries, for our foreign policy relationships. You know, (talking about) building that wall between Mexico and the United States has built a wall between the United States and Latin America. It has done more damage already than one could imagine," Stiglitz told CNBC.