ATLANTA (AP) There’s plenty of worry among Democrats about whether 81-year-old President Joe Biden is up to the job itself or the task of defeating Donald Trump.

Previous presidential campaigns offer lessons. None convey reasons for optimism.

Going back to Lyndon B. Johnson in 1968, several presidents eligible for reelection faced significant primary challenges or questions about whether they should run again. George H.W. Bush, Jimmy Carter and Gerald Ford pushed forward and won their nominations, only to be defeated in November. Johnson opted to withdraw and Democrats lost anyway.

Biden had no real primary fight. But his allies now acknowledge how poorly the president performed in his debate against Trump. They’ve fretted privately about Biden’s ability to serve until he is 86, and, more immediately, whether he can keep the job by defeating the Republican former president  himself a 78-year-old saddled with a felony conviction, other indictments and voter concerns over his values and temperament.

History’s cautionary tale is clear: Presidents in their first term who are still grappling to unite and reassure their own party by this stage rarely secure a second term.

Consider George H.W. Bush and the pivotal ‘culture war’ of 1992. Bush, an Ivy League-educated Episcopalian, maintained a moderate stance within the Republican Party. He was never fully embraced by the Christian right or staunch advocates of anti-tax and small-government policies.

In the lead-up to his victory in 1988, George H.W. Bush appealed strongly to the right wing with his famous pledge: “Read my lips: no new taxes.” His popularity soared in 1990 following a swift U.S. military success that expelled Iraq and Saddam Hussein from oil-rich Kuwait. However, within months, Bush faced criticism after reneging on his tax promise, coinciding with a mild economic downturn that left him vulnerable.

During the primaries, challengers emerged, including Steve Forbes, known for his anti-tax stance, and Pat Buchanan, a commentator and Christian conservative. Despite winning most primaries, Bush’s victories often lacked significant margins. Buchanan, rather than fully endorsing Bush, used his speech at the GOP convention to rally religious conservatives in what he termed a “culture war” against Clinton, liberals, and secularism a departure from Bush’s message of a “kinder, gentler” nation and a sign of growing division within the Republican ranks.

Arkansas Governor Bill Clinton, the Democratic challenger, aggressively criticized President Bush for being disconnected from the concerns of middle-class Americans. Additionally, billionaire Ross Perot entered the race as an independent candidate.

On Election Day, a significant majority 62.6% of voters chose not to re-elect Bush. Bill Clinton secured a substantial victory with 370 electoral votes, marking the second-highest total for any Democrat since 1964.

Switching gears to another historical example, in 1980, Jimmy Carter faced challenges during his bid for re-election against Ronald Reagan. As a former governor of Georgia, Carter was seen as a moderate Southerner who stood somewhat outside the traditional liberal Democratic establishment. His initial nomination and eventual win over the Republican incumbent Gerald Ford in 1976 were more about his promise to restore honesty in government following the disillusionment caused by the Vietnam War and the Watergate scandal.

After initial legislative achievements, Jimmy Carter faced discontent among Democrats in Washington. The global economy saw inflation, rising U.S. unemployment rates, and increased interest rates, contributing to a decline in Carter’s popularity.

Joe Trippi, who worked on the Kennedy campaign in 1980, reflected, “Carter was never anticipated to be embraced by the establishment.”

In 1980, Senator Ted Kennedy launched a primary challenge against President Jimmy Carter, igniting enthusiasm among young progressives who admired Kennedy’s older brothers. Carter famously declared, “I’ll kick his ass,” as he fought to secure enough delegates for the Democratic nomination amidst the backdrop of the Iran hostage crisis.

Despite Carter’s delegate victory, Kennedy’s convention speech focused more on rallying his supporters than on reconciling with the incumbent. His memorable declaration, “The work goes on, the cause endures ” and the dream shall never die,” underscored Carter’s vulnerabilities.

In the general election against Republican Ronald Reagan, Carter managed to win only six states and Washington, D.C.

Turning back to 1976, Gerald Ford faced a significant challenge from Ronald Reagan in the Republican primary. Ford, a mild-mannered politician from Michigan, had a distinctive path to the White House. He was elevated from House leadership to the vice presidency by President Richard Nixon in 1973 following Spiro Agnew’s resignation due to corruption. Ford then became president in 1974 when Nixon resigned in the aftermath of the Watergate scandal.

Gerald Ford’s presidency was marked by controversy, notably his pardon of Richard Nixon. During his tenure, the country faced challenges such as inflation, high unemployment, and volatile energy markets. Ford, who had never participated in a national campaign before assuming the presidency, quickly had to prepare for his own election bid.

Coming from the center-right of Capitol Hill, Ford represented a Republican faction that generally accepted the expanded role of the federal government initiated by Franklin Delano Roosevelt’s New Deal. In contrast, Ronald Reagan was rallying conservatives who opposed FDR’s policies and were skeptical of the Civil Rights Movement and social changes of the 1960s and 1970s.

During the 1976 primaries, Ford secured victory in 27 contests compared to Reagan’s 24. Ultimately, Ford amassed 1,121 delegates, just 43 more than Reagan. Reagan’s strength was particularly evident in the South, the most conservative region of the country, where he dominated most primary elections.

In the fall campaign, Gerald Ford made a late surge against Jimmy Carter but ultimately fell short, with Carter carrying the South. This set the stage for Ronald Reagan to emerge as the leading figure in the Republican Party, poised to claim the nomination four years later.

Looking back further to Lyndon B. Johnson’s decision in 1968 to step aside offers another perspective. Johnson, thrust into the presidency after John F. Kennedy’s assassination in 1963, decisively defeated Barry Goldwater in 1964. His presidency was marked by significant legislative achievements, including the Civil Rights Act, Voting Rights Act, Medicare, and Medicaid. However, Johnson’s escalation of U.S. involvement in Vietnam and challenges navigating social changes eroded his popularity.

Johnson’s announcement on March 31, 1968, that he would not seek another term came after disappointing showings in early primaries. This decision paved the way for a tumultuous Democratic nominating process, with Senator Robert F. Kennedy gaining momentum until his assassination moments after winning the California primary in June.

The chaotic Democratic convention in Chicago ultimately selected Vice President Hubert Humphrey to challenge Republican Richard Nixon. Nixon, who had previously lost to John F. Kennedy in 1960 and faced defeat in the 1962 California governor’s race, capitalized on dissatisfaction with the Johnson administration and narrowly defeated Humphrey in the general election. Independent candidate George Wallace also played a significant role.

The aftermath saw the Democrats suffer defeat despite Nixon’s controversial presidency, which would later end in resignation. This historical context suggests that while parallels can be drawn to past transitions and challenges within the Democratic Party, each political era presents unique dynamics and outcomes.