The former US vice-president Joe Biden has accused “demagogues and charlatans” of stirring up voters’ fears just as they did in the 1930s as the issue of migration convulses politics on both sides of the Atlantic.

Biden, seen as a potential Democratic party candidate against Donald Trump in 2020, did not mention the US president by name but linked his anti-immigrant drive and that of European populists and the far right to pre-war fascists who were willing to create scapegoats to retain their grip on power.

“In ways that evoke memories of the 30s, frustrated and disaffected voters may turn instead to strongmen,” he told a conference in Copenhagen. “Demagogues and charlatans step up to stoke people’s legitimate fears and push the blame always on the other. There always has to be scapegoats. Now it is immigrants, the outsider, the other.”

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Biden said: “Rather than some dramatic assault on democracy, however, ... our institutions and freedoms are slowly but determinedly being sanded down, little by little, each small step designed to curb institutional safeguards and concentrate power in the hands of individual leaders.

“All round the world, repressive governments are borrowing from one another’s playbook, deriding a critical free press as fake news and questioning, indeed delegitimising, an independent judicatory, hamstringing civil society with increasingly repressive laws. Taken together, they threaten democratic ideals that have been the foundation for the western world.”

Biden is heading a transatlantic commission on defending democracy and was effectively launching it at a conference attended by former western leaders including Tony Blair and Nick Clegg from the UK, Stephen Harper of Canada and José María Aznar of Spain.

Biden has previously criticised the Republican party’s “fake nationalism” under Trump but in Copenhagen he urged greater understanding of the concerns of blue-collar workers over matters including globalisation and migration.

He said: “Voters [are] worried that politicians are not looking out for them. Borders seem less real. Terrorist attacks feel inescapable. There are fears about unrelenting migration. Some are concerned that the demographic and cultural foundations of their society are going to be forever changed or erased.”

He said globalisation had deepened rifts, divorced productivity from labour and created less demand for low-skilled labour. “When people see a system dominated by elites and rigged in favour of the powerful, they are much less likely to trust democracy can deliver,” he said.

Biden was unflinching in his criticism of the slide away from democracy in central and eastern Europe: “In Poland, the ruling party portrays checks and balances as impediments to achieving key national goals and then uses that pretext to stack the courts with political appointees.

“Hungary’s leaders blame nefarious outsider influences [for] Hungary’s social ills and hold up illiberal democracy as the best model.”

He praised the European commission’s plans to withhold budgets to countries that do not stand by democratic values as “sharp, timely and important”.

The bulk of the Biden commission’s work will be into Russian interference in elections and how the west can protect itself without undermining democracy.

Facebook Twitter Pinterest The former Spanish PM José María Aznar (centre) and former UK deputy PM Nick Clegg (right) also spoke at the conference. Photograph: Keld Navntoft/EPA

He said the depth of Russian interference in the 2016 US elections was becoming clearer by the day. “The Kremlin wants to weaken democratic institutions, divide Europe and its core institutions of Nato and the EU, and delegitimise the rules-based international order.

“That’s how Putin believes he can maintain his grip on power. Putin is more than happy to use our greatest strength – our open and vibrant societies – against us, using the internet and social media to spread disinformation and exacerbate internal divisions.”

In a warning that democracy may be on the wane in the west, the conference organisers released a poll showing people in illiberal states were more likely to think government was on their side than those in free democracies, possibly reflecting the lack of debate in those societies.

Clegg, the former deputy prime minister who sits on the Biden commission, said democracy had suffered a body blow because millions of voters around the world felt “the system screwed up in the banking crisis and they are now paying the consequences through no fault of their own”.

He said Britain was going through “an unprecedented experiment” with its decision to leave the EU. “There is no other democracy anywhere in the modern world that invites its population to vote on its future, decides by a wafer-thin majority to go in a completely different direction to where it has been going for 40 years against the explicit and stated wishes of those that have to inhabit that future – the young.”

Blair warned that faith in democracy was in decline, saying: “There is more than a mild flirtation in the west with what we can loosely call rule by the ‘strongman’ ie the leader who has supreme control over the levers of government, sets a direction and dismisses all opposition to it with varying portions of disdain or repression,” the former prime minister said “We must understand the attraction of this model since its footprint is growing.”

Harper, the former Canadian prime minister, said: “Democracy is ultimately justified on its record and for a lot of our citizens in the last 30 years their outcomes have not been very good for a long period of time.”

Facebook Twitter Pinterest Tony Blair at the summit in the Royal Theatre House in Copenhagen. Photograph: Scanpix Denmark/Reuters

The Danish prime minister, Lars Lǿkke Rasmussen, said he was less worried by the assault on western democracy from Russia than one from allies within the western alliance. He pointed to “the tendency to withdraw from international negotiated agreements and forums – Paris, Iran ... and now the human rights council”.

In attacking the G7 and questioning Nato “uncertainty is inflicted on the very foundations of our progress”, he said, adding there had to be an end to “the ambition of only putting your own country instead of seeing the big picture”.

Brexit, he said, reflected the same attitude: “A desire to maximise what you gain and minimise what you give.”