Joe Biden has issued a full-throated denunciation of the US supreme court’s decision to grant his predecessor, Donald Trump, broad immunity from criminal charges of trying to overturn the 2020 presidential election, calling it a “dangerous precedent” that overturned the basic principle of equality before the law. In a 5-minute speech from the White House, Biden said the 6-3 ruling “undermined the rule of law” and rendered a “terrible disservice to the people of this nation” because it means Trump is much less likely to be held legally accountable for inciting a mob to launch a deadly attack on the US Capitol on 6 January 2021. Citing and echoing the words of the liberal and dissenting supreme court justice, Sonia Sotomayor – who criticised the ruling – the president said: “I dissent.” The ruling meant it would fall to voters to decide if Trump, the presumptive Republican nominee in the forthcoming presidential election, was worthy of being entrusted once again with the presidency, said Biden, using the opportunity to present the electoral choice in character terms. “This nation was founded on the principle that there are no kings in America,” said Biden, in his public remarks since a weekend family gathering to discuss the future of his own candidacy, seemingly imperiled following a disastrous performance in a televised debate with Trump last week. “Each, each of us is equal before the law. No one, no one is above the law, not even the president of the United States. “With today’s supreme court decision on presidential immunity that fundamentally changed for all practical purposes. Today’s decision almost certainly means that there are virtually no limits to what the president can do. This is a fundamentally new principle. It’s a dangerous precedent, because the power of the office will no longer be constrained by the law, even including the supreme court in the United States, the only limits will be self-imposed by the president alone.” Subtly casting the issue in an electoral context, Biden said the ruling forced voters to confront the question of whether Trump has the character to constrain his own behavior if he is returned to the White House. And in what may have been a cryptic message to those in his own party questioning the viability of his candidacy, he compared his opponent’s character traits unfavorably with his own. “Now the American people have to do what the court should have been willing to do and will not,” he said. “The American people have to render a judgement about Donald Trump’s behavior. “The American people must decide whether they want to entrust … once again, the presidency to Donald Trump now knowing he’ll be more emboldened to do whatever he pleases, whenever he wants to do it. “I know I will respect the limits of the presidential powers I have had for three and a half years, but any president, including Donald Trump, will now be free to ignore the law.” The occasion gave Biden, 81, a chance to reassert the authority of the presidential office after the crisis that has engulfed his candidacy in recent days, with Democrats questioning whether he should be replaced as the party’s candidate in the wake of his feeble debate performance, when he failed to effectively counter Trump’s multiple false statements, frequently misspoke and sometimes appeared stuck for words. He used Monday’s White House speech to issue a broader attack against the supreme court, whose recent rulings have stemmed from a conservative majority established largely because of three rightwing justices appointed to the bench by Trump. “This decision today has continued the court’s attack in recent years on a wide range of long established legal principles in our nation – from gutting voting rights and civil rights to taking away a woman’s right to choose, to today’s decision that undermines the rule of law of this nation,” he said.