Washington (CNN) Former Vice President Joe Biden offered a scathing indictment of Donald Trump and his administration Thursday night, suggesting the President is leading the US "down a very dark path" of geopolitical decline.

"We really worry that we're walking down a very dark path. It's not alarmist. We're walking down a very dark path that isolates the United States on the world stage and, as a consequence, endangers -- not strengthens -- endangers American interests and the American people," Biden said.

Biden, who was being honored with the Center for Strategic and International Studies' Zbigniew Brzezinski Annual Prize, referred to Trump by name only a handful of times in his blistering condemnation -- a strategy he, former President Barack Obama, former first lady Michelle Obama and others have used to criticize the 45th President.

However, his condemnation was unmistakeably pointed. Biden portrayed Trump as a "charlatan" who had preyed on America's worst ills to gain the Oval Office and was threatening to undo decades of precedent and the alliances that the US has forged.

"The appeal to populism and nationalism is a siren song, a way for charlatans to aggrandize their power, raise themselves up, break down those mechanisms that are designed within our Constitution and internationally to limit the abuse of power and destabilize the world," Biden said. He later denounced Trump's attacks on the press and the courts.

Biden lambasted Trump's speech to the United Nations General Assembly, in which he called North Korea's Kim Jong Un "rocket man" and threatened to "totally destroy" that nation if forced to defend the US or its allies.

"Trading insults. Deploying taunting nicknames. Promising to 'totally destroy' a country of 25 million people. Such erratic action only worsens the crisis and rejects the possibility of diplomacy and actively increases the risk of conflict," Biden said. He suggested that the rhetoric was reminiscent of those that preceded World Wars I and II.

"To stand in the well of the General Assembly and wave the flag of narrow nationalism while warning of a future vulnerable to 'decay, dominion and defeat' marks a dangerous revision of political small-mindedness that led the world to consume itself in two world wars in the last century, and it abandons America's hard-won position as the indispensable nation, as a leader that inspires more than fear," Biden said.

On reports that Trump intends to "decertify" the Iran nuclear deal , Biden said the move would isolate the US, not Iran. Moreover, that action, coupled with the US exit from the Paris climate accord and the Trans-Pacific Partnership, could cause the rest of the world to "(call) into question what the word of the United States is actually worth."

Biden slammed Trump for his repeated refusal to condemn Russia's interference in the US political process.

"So far, President Trump has been unwilling to call out (Russian President Vladimir) Putin for Russia's meddling, even in our own democratic process, or criticize his action," he said. "Think of that. Think of the signal it sends around the world for God's sake."

Speaking more generally, Biden painted a picture of an administration in foreign policy disarray, citing their "ideological incoherence, inconsistent and confusing messaging, erratic decision-making, unwillingness or inability to solve problems caused by understaffing."

"When's the last time, in the State Department, you can stand on the seventh floor and yell and hear an echo?"

"For as long as I've been in politics, the United States has earned the respect of the world when we've led with our values. We haven't been perfect by any stretch of the imagination ... but on balance, the world has always looked to us, believing that we mean what we say even if we don't always live up to it," Biden said, almost shouting.

"It's irresponsible. It's this brand of zero-sum thinking that I find the most disturbing and dangerous," he added.

"Rather than building a shared narrative of freedom and democracy that inspires nations to unite in common goals, this administration casts global affairs in a dog-eat-dog competition, like it's a competition -- who gets that plot to build the new high-rise building," Biden said, dinging Trump's background as a real-estate developer.

Biden said it was essential for the US not only to remember its core values but to advocate for them.

"Think of all who came, and all those who came, before you! They had courage. They had a sense of optimism. They were persistent. That's who the hell we are!" he said. "Treating everyone with dignity without exception, respecting the rule of law, modeling an unassailable commitment to freedom of speech and freedom of the press."

"We can't let the current distractions keep us from keeping an eye on the horizon as well," he added, suggesting that he and Obama could be increasingly likely to speak out against Trump.

"I really feel incredibly strongly that the women and men sitting before me, who have been the intellectual backbone of the foreign policy establishment in this country for decades, have to start to speak out," he said. "President Obama and I have been very quiet and respectful, giving the administration time. Some of these roots are being sunk too deeply. I believe it's time to challenge some of the dangerous assumptions that are attempting to replace that liberal world order."