After US President Joe Biden’s stumbling and unconvincing performance during the debate with former President Donald Trump on June 27, it is no exaggeration to say that the future of our planet may depend on a decision he must make. Does he want to go down in history as the man who was responsible for the disastrous consequences of a second Trump presidency? Will he join others whose lifelong efforts to do good were undone by their refusal to put the public interest first?

For progressives like me, Ralph Nader was once a hero. His first book, “Unsafe at Any Speed,” was a devastating expose of how the US auto industry put profits ahead of safety. Nearly 50,000 people were killed on US roads in 1965, the year it was published. The book spurred a crucial public debate that led to legislation to improve road safety. By 2011, the death toll on US roads had fallen to 35,000, and, on a per capita basis, was less than half what it had been 45 years earlier.

Nader deserves much of the credit for changes that have spread worldwide. The total number of lives saved since the 1960s must now be in the tens of millions; the number of injuries prevented will be several times higher.

Yet that is not Nader’s legacy today. The US presidential election in November 2000 was a contest between the Democrat Al Gore, who was the incumbent vice president, and George W. Bush, the Republican nominee. Nader, though, rejected Gore, even though Gore had long made environmental protection his overriding concern, and ran for the Green Party. Whereas Gore had written the 1992 bestseller “Earth in the Balance,” a book that urged strong action to address climate change and other ecological crises, Bush was the candidate of the oil industry.

When the votes were counted, the election came down to which candidate would win Florida. Bush won the state, and thus the presidency, by 537 votes, after the US Supreme Court stopped a recount. In Florida, Nader received 97,488 votes. There can be no doubt that if Nader had not been a candidate, many more of his votes would have gone to Gore than to Bush, and Gore would have been elected president.

One of Bush’s first acts as president was to announce that the US would not implement the Kyoto Protocol, which set binding emissions targets for industrialized countries. Without a strong lead from the US, international efforts to reduce greenhouse gases soon fell apart, and they have never recovered to the level necessary to avoid catastrophic climate change.

As a result, despite the immense good that Nader did as a campaigner for road safety, his overriding legacy is that he prevented the election of the only American presidential candidate who regarded climate change with the seriousness that it required, at a time when the window of opportunity to prevent disaster was wider than it is today.

Likewise, when Ruth Bader Ginsburg was a Supreme Court justice, I admired her for her advocacy of women’s equality and reproductive rights. By 2013, however, she was 80, the oldest person on the Court, and had twice been treated for cancer. At a private lunch at the White House, President Barack Obama told her that at the coming mid-term elections, the Democrats were likely to lose control of the Senate. The implication was obvious: if Ginsburg were to resign, Obama could appoint a much younger replacement who would uphold, for decades to come, the liberal values that she and the president shared.

Others made the same suggestion to Ginsburg, but she did not resign. After her death, President Trump nominated her replacement, Amy Coney Barrett. The conservative majority on the Court overturned Roe v. Wade, which had extended constitutional protection to abortion for nearly a half-century, and soon state governments imposed draconian restrictions. Now that conservative majority is undermining the power of the Environmental Protection Agency to do its job.

Biden said in the recent debate that he stood for president in 2020 not because of a desire for power, but to stop Trump, and that he is running again for the same reason. But the debate showed all too clearly that he is suffering cognitive decline and cannot possibly serve as a competent president for another four years.

If Biden is true to his word, and stopping Trump from regaining the presidency is his overriding goal, he needs to announce that at the Democratic Convention in August, he will release his delegates from their obligation to vote for him, and instead ask them to vote for the candidate with the best chance of defeating Trump. Gretchen Whitmer, the popular governor of Michigan, or Gov. Gavin Newsom of California, and probably others would have a better chance of stopping Trump than Biden now has.

Peter Singer

Peter Singer is a professor of bioethics at Princeton University and the founder of the organization The Life You Can Save. The views expressed here are the writer’s own. -- Ed.

(Project Syndicate)