The new president was in trouble. After a fast start on his legislative agenda, his job approval declined through the first and second years of his administration. Inflation was uncomfortably high, and the public’s mood about the economy had soured.

In the midterms, the president’s party suffered large losses in the House. As the third year of his presidency began, his job approval had sunk to 35%, and a national poll conducted later that month found him trailing his principal opponent for the presidency by 9 points.

This...

President George H. W. Bush and President-elect Bill Clinton at the White House.

Photo: Diana Walker/Getty Images

The new president was in trouble. After a fast start on his legislative agenda, his job approval declined through the first and second years of his administration. Inflation was uncomfortably high, and the public’s mood about the economy had soured.

In the midterms, the president’s party suffered large losses in the House. As the third year of his presidency began, his job approval had sunk to 35%, and a national poll conducted later that month found him trailing his principal opponent for the presidency by 9 points.

This president was Ronald Reagan. A year later, his campaign ad, “Morning in America,” captured the improving public mood. Later that year he defeated Walter Mondale in one of the greatest landslides in American history.

Modern U.S. history is replete with such reversals of fortune, which is why today’s hand-wringing about the Biden presidency is—to quote Mark Twain’s reaction to erroneous reports of his death—premature. Consider:

As the third year of his presidency began, George H.W. Bush was riding high. His job approval stood at 58%, and it surged to nearly 90% as he brought the Gulf War to a swift and successful conclusion. A year later, after a divisive GOP convention, his approval sank to 29%, and despite a partial recovery in the next three months, he lost the presidential election to Bill Clinton by 5 points.

Mr. Clinton got off to a rough start as he appeared to govern more as a traditional liberal than as the reform-minded New Democrat he proclaimed himself to be during the campaign. After a bumpy two years, he led his party to a huge loss in 1994, handing control of the House to Republicans for the first time in four decades.

At a news conference in April 1995 that only one major network cared to cover, Mr. Clinton felt compelled to defend himself by proclaiming that “I am relevant. The Constitution gives me relevance.” While defending Democratic priorities such as Medicare, Medicaid, education and environmental protection against Republican attacks, he refocused his presidency on welfare reform and endorsed a balanced budget. Eighteen months later, after tacking to the center and benefiting from a strong economic surge, he won re-election by 8 points over former Sen. Bob Dole.

Barack Obama also encountered difficulties early in his presidency. After his stimulus bill passed mostly along party lines, it took nearly a year to reach consensus among Democrats on his signature legislation, the Affordable Care Act, which was unpopular for years. Major environmental legislation died in the Senate.

By the midterm elections of 2010, his job approval had fallen by 20 points from its peak, and Democrats lost 63 House seats, the most since 1938. Yet over the next two years, despite a painfully slow recovery from the Great Recession, Mr. Obama’s standing with the public gradually improved, and he ended up winning re-election by a comfortable margin.

Which brings us back to Mr. Biden. His presidency has been dragged down by unforced errors such as the chaotic withdrawal from Afghanistan, unanticipated events such as the outbreak of the Delta variant, misjudgments such as minimizing the threat of inflation for too long, and the public perception that he is less competent and more liberal than he appeared during the campaign. Whatever happens over the next 11 months, it seems inevitable that Republicans will control the House after the midterm elections. A new poll conducted by Donald Trump’s super PAC found the former president leading Mr. Biden in five swing states.

This doesn’t mean he is fated to lose the presidency in 2024, assuming he runs. Everything depends on whether he crafts a political recovery plan and sticks to it. This must begin with clear, sustainable policies on immigration, crime, inflation and education, issues he has ducked or muddled. It means making decisions without dithering and implementing them without glitches that undermine public confidence. Mr. Biden must convince the American people that he is the man they thought he was—a competent centrist—when they cast a record 85 million votes for him a year ago.

Above all, the president and his advisers must heed the lesson of last month’s elections: Swing voters exist, and they are paying attention. They care about a lot more than Donald Trump, and they will shift their votes if they don’t like what they’re seeing. Unless Mr. Biden is reconciled to being a one-term president, these Americans must be his polestar.

The only thing worse than the President's approval rating is that of his vice president, Kamala Harris, whom it's reported the Biden team accuse of dysfunction and a lack of focus. Images: AFP/Getty Images Composite: Mark Kelly The Wall Street Journal Interactive Edition