This weekend, first lady Jill Biden has a momentous choice to make. Does she encourage her husband to overlook his personal well-being, recover from last weeks debate debacle, and keep up the campaign until November? Or does she persuade him to step aside, and yield the nomination to someone else?

Biden isnt the only first lady to face a choice like this one. As their wartime husbands undertook reelection campaigns, both Eleanor Roosevelt and Lady Bird Johnson faced difficult decisions, and they came to very different conclusions. Roosevelt supported her husbands candidacy in 1944 without reservation, although she believed that he might not survive the term in office that followed. Johnson, in contrast, was the main voice in her husbands inner circle calling for him not to run in 1968 for a second full term.

Each historical circumstance is different, but first ladies have unique influence over their husbands choice to embark on a presidential campaign, and over the presidency itself. As scholars of gender, politics, and power, we strongly advise Jill Biden to adopt Lady Bird Johnsons approach and to regard Eleanor Roosevelts as a decidedly cautionary tale.

Franklin D. Roosevelt was gravely ill by the spring of 1944. He had severe, long-untreated hypertension, which resulted in an enlarged heart as well as difficulty breathing, sleeping, and concentrating during the day. He may also have had cancer that metastasized to his stomach. His doctors were cagey, underplaying his diagnosis and his recommended treatment. Regardless, the president, his closest advisers, and his family members knew for the entirety of the election year that his health was subpar.

Read: Bidens loved ones owe him the truth

Eleanor Roosevelt was a believer in the vigorous life, and a nonbeliever when others expressed frailty or claimed that they needed rest. Still, she knew that her husband was not his former robust self. She nevertheless believed that he should run. Perhaps sounding more resolute or sanguine than she felt, the first lady told a friend that she believed in FDR: If he can accomplish what he set out to do, and then he dies, it will have been worth it.

That calculation made sense to the first lady and her husband in 1944. The country was still at war. Allied forces were on the advance, but the tricky negotiations with Winston Churchill and Joseph Stalin over the meaning of their imminent victory had just begun. President Roosevelt had successfully assumed the mantle of Dr. Win-the-War. Perhaps Eleanor, even more than he, eagerly anticipated the time when he could bring Congress along in fulfilling the domestic agenda that he had only half-accomplished before the rise of Hitlerism in Europe.

Campaigns were different then. There were no head-to-head, 90-minute-long televised debates. In April and May 1944, Roosevelt even took a rest cure for almost a month, sleeping nearly 12 hours a night. The three wire-service journalists tagging along kept their distance and allowed the president peace and quiet (as well as unreported visits from his former mistress, Lucy Mercer Rutherfurd).

A three-time Democratic standard-bearer, Roosevelt faced no serious opposition before or at his partys convention. In the general election, the Republican Thomas Dewey called the administration a regime of tired and quarrelsome old men. The president felt the need to campaign actively only in the month prior to the election. He gave barnstorming addresses and toured large East Coast cities in an open car during rainstorms, demonstrating his health even as he imperiled it. Roosevelt beat Dewey by more than 3 million votes. He died less than six months later, the prescriptions of Dr. New Deal still largely unfilled.

In Lyndon B. Johnsons case, the country was also at war, although an unpopular one that the United States was by many measures losing. But LBJs decision to forgo the 1968 election didnt have its roots in the debacle of Vietnam, in Eugene McCarthys standout showing in the New Hampshire primary, or in Robert F. Kennedys entry into the race that spring. Instead, it traced back to a May 1964 memo that Lady Bird Johnson wrote to her husband, who was then wavering about the upcoming convention in Atlantic City, New Jersey. Lady Bird proposed a timeline for his presidency, specifically casting ahead to February or March of 1968 as the right moment for him to announce that he would not run for a second term. He was only five months into his post-assassination presidency, and already pressure to escalate in Vietnam and a Senate filibuster on civil rights signaled to both him and his wife that LBJ might not be able to hold on to the goodwill of the country over the next eight years.

As with Roosevelt, health was a major concern. Lyndons heart disease and depression were always top of mind for both Johnsons. His father and his uncle had each died of heart disease before turning 60. In 1955, a massive heart attack nearly killed him. At the time, he was merely the Senate majority leader. His chronic depression, the black beast, as Lady Bird called it, shadowed him and made him ever more reliant on his wife for emotional ballast. Once in the White House, he also relied on her help to clarify his political possibilities and limitations. Even in 1965, with two civil-rights bills passed, the Great Society in full gear, and Vietnam yet to compel a sizable protest movement, a bout with depression after gallbladder surgery moved LBJ, with Lady Bird at his hospital bedside, to secretly dictate his resignation to Abe Fortas, his adviser and by then an associate justice of the Supreme Court.

Fast-forward to October 1967, when Lady Bird began her private campaign to find the right time to persuade LBJ to make her strategy public, and when Lyndon himself began to discuss the prospect with two more confidants. By 1968, now a doting grandfather and the father-in-law of two men bound for service in Vietnam, he was speaking often with Lady Bird about how to survive Washington long enough for their growing family to thrive in their post-presidency. On March 31, 1968, when Lyndon surprised even his closest staff in announcing that he would not run for a second term, his statementtucked into a speech about Vietnamwas an amalgam of drafts, including two that Lady Bird had written herself.

Lady Bird approached her husbands decision with a combination of clarity and ambivalence. She wanted him alive and well for a peaceful retirement and saw how the presidency was destroying that prospect. Yet she knew that, ultimately, the decision was his and his alone. Lyndons decision to abstain from a run at a second term, and not to attend the Chicago convention that Augustnot even for a valedictory speechwas muddled by his desire to deepen his social and civil-rights policy agenda and his belief that he could extricate the country from Vietnam. But Lyndon had been ambivalent about his own personal stamina and national standing for the position since 1960, when John F. Kennedy added him to the ticket. Lady Bird was, in effect, leaning on an open door as she pressed LBJ to execute her 1964 strategy, enlisting the likes of Fortas, Texas Governor John Connally, his doctors, and her daughters in her campaign.

Jill Biden is dealing with a very different president. Historians may quibble, but Joe Bidens quest for the presidency, however the narrative has been shaped by Biden staff and family members, reads as a straight line of ambition and effort, thwarted at turns, and finally manifest. His wife has been central to this success. But now her own legacy rides on leading him out of his historically successful presidencynot just for her sake or for his, but for that of American democracy.