Joe Biden signals he is done being 'quiet and respectful' as he tears into Trump: 'We’re walking down a very dark path'

Former Vice President Joe Biden has launched a strident attack on Donald Trump’s foreign policy, saying it has endangered America and hinted he and Barack Obama are set to offer more outspoken criticism of the man who succeeded them in the White House.

In a speech to a foreign policy think tank in Washington DC, the man who may still be considering a presidential run in 2020, said it was time for experts to raise their voices and speak out.

“We are walking down a very dark path. It’s not alarmist,” he said. “The isolation of the United States on the world stage…as a consequence endangers - not strengthens - American interests and the American people.”

He added: “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.

“President Obama and I have been very quiet and respectful, giving the administration time, but 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.”

Both Mr Biden and Mr Obama have been watchful of their public criticism of the Trump administration since they left the White House. Mr Obama spoke out over the effort to scrap his landmark healthcare plan and about a proposal to deport so-called “Dreamers” as part of an immigration crackdown.

Yet the comments by Mr Biden on Thursday in Washington, as he accepted an award form the Centre for Strategic and International Studies think tank, are an insight into the deep concern felt by many over Mr Trump’s foreign policy.

In recent weeks, it has become ever more clear of the gap between Mr Trump and his most senior diplomat, Secretary of State Rex Tillers. This week, Mr Tillerson was obliged to hold a press conference to deny a report by NBC News that he had considered resigning from the cabinet this summer and considered the President “a moron”. While he did not specifically deny making the comment, he said Vice President Mike Pence had not had to talk him out of quitting.

After months of reflection and consideration, Mr Biden, 74, decided against contesting the 2016 presidential election, a decision he has since suggested was wrong. There are many in the Democratic Party who want him to consider a run in 2020, despite his age.

Mr Biden, who reached the top in American politics from hardscrabble roots, said in his speech he knew many Americans felt left behind by globalisation, and that Mr Trump had been able to tap into such concerns.

“The appeal to populism and nationalism is a siren song, a way for charlatans to aggrandise their power, raise themselves up, break down those mechanisms that were designed, whether in our constitution or internationally, to limit the abuse of power, and destabilise the world,” he said.

Referring to Mr Trump’s history as a New York property developer, Mr Biden said: “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.”

He said the actions the Trump administration were making it more difficult for the US to face current challenges, undermining the country's credibility by planning to back out of the Paris climate deal, questioning the US commitment to NATO and threatening to destroy the Iran nuclear deal.

He added: “This administration is calling into question what the word of the United States is actually worth.”