Former Vice President Al Gore Albert (Al) Arnold Gore4 inconclusive Electoral College results that challenged our democracy Fox's Napolitano: 2000 election will look like 'child's play' compared to 2020 legal battles Who calls an election? Why we need patience and nonpartisanship this time MORE warned on Monday that the U.S. is going through a "challenging time" under President Trump.

During an interview on NBC's "Today," Gore raised concerns about the impact of Trump's presidency on the country's standing.

“We’ve never had a president who's deliberately made decisions, the effect of which is to tear down America’s standing in the world, starting with his withdrawal from the Paris agreement,” Gore said.

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“The climate crisis is by far the most serious challenge we face, but he’s also undermined our alliances, such as NATO, and hurt our standing in the world in many ways.”

The months ahead will be a test for the American people, he added.

Gore said he had hoped Trump would "come to his senses" on the Paris climate agreement.

"But I was wrong."

He also hasn't spoken with Trump since the president announced his decision to withdraw the U.S. from the Paris agreement earlier this year.

Gore, who has become a leading advocate for a global response to climate change, chided Trump's decision last month to withdraw from the Paris agreement.

He called it a "reckless and indefensible action" and said it "undermines America's standing in the world."

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