Senator Chris Coons expressed concerns about President Trump's approach in negotiations with the Taliban to try to end the 18-year conflict in Afghanistan, saying his fellow Delaware Democrat and longtime friend Joe Biden would be better equipped to broker a peace agreement supported by generals and diplomats alike.

"I'm concerned that our president isn't listening to his generals, to his diplomats, to the intelligence community," Coons said Sunday on "Face the Nation." "Frankly, that's largely why General Mattis, for whom I have huge respect, resigned in protest. [It] was our president's tendency to make abrupt decisions without knowing the context or the region, and without relying on the advice of the skilled diplomats and generals we have."

Coons said he's particularly worried about what he believes is Mr. Trump's tendency to negotiate deals with foreign leaders by himself, with little or no advice from government experts in their respective fields.

If elected president, Biden would rely on the expertise of the diplomatic corps, the military and the intelligence community to make important foreign policy decisions, Coons argued. Coons has endorsed his former colleague's presidential bid.

"He has spent decades in foreign service, as has General Mattis, as both a senator and a vice president," Coons said, referring to Biden and James Mattis, the former defense secretary. "Look, history moves and if you don't learn from history you can't shape it. One of the things I most respect about General Mattis is how deeply read he is in history. One of my concerns about our current president is his shallow understanding of recent history."

For months, the Trump administration has been holding talks with representatives of the Taliban insurgency in Afghanistan to eventually bring an end to what has become America's longest military engagement. Last week, the U.S. envoy there, Zal Khalilzad, announced his team had reached an agreement "in principle" with the Taliban to withdraw around 5,000 U.S. troops within 135 days of a deal being signed.

But on Saturday, Mr. Trump, citing a suicide bombing in Kabul on Thursday that killed an American soldier and 11 others, called off a secret meeting he was slated to host at his Camp David retreat on Sunday with Afghan government officials and Taliban leaders.

The meeting's revelation provoked some criticism from lawmakers opposed to inviting members of the Taliban to negotiate on American soil and exacerbated concerns among some Republicans and Democrats that the president — who has publicly railed against U.S. intervention abroad — would have agreed to a precipitous withdrawal of U.S. troops, which critics say could jeopardize U.S. national security.

Coons said there needs to be a bipartisan effort when it comes to diplomacy in Afghanistan to "prevent terrorism from coming to our shores again."

"This frankly is also why I believe Joe Biden would be our best next president. I think he has deep and wide experience in foreign policy and understands the values of our alliances," he added.