President Joe Biden’s stumble across the stage after speaking at the Air Force Academy on Thursday will certainly feature prominently in Republican campaign ads aimed at reinforcing the theme, already gnawing at even his most ardent supporters, that Biden is too old and frail for another four years. The unpopularity of backup, Vice President Kamala Harris, only aggravates the problem.

To bolster his chances for reelection, Biden needs to engage in some out-of-the-box creativity.

Biden might rescue his faltering hope of reelection in one seemingly impossible way — asking the highly popular, former President Barack Obama to step in to replace Harris on the 2024 ticket.

This isn’t the first time the idea has been floated. There was talk about just such a ticket as early as 2015, before the Obama-Biden administration had even ended.

I think that Obama has been wrongly excluded from discussion about the 2024 race because it is simply assumed that he is constitutionally barred from running as a candidate on the national ticket. That is a mistake. As I will explain, the Constitution permits this kind of gambit — and, despite the apparent unlikelihood of it happening, both Biden and Obama owe it to the country to consider using it.

Biden continues to sink in the polls, with a recent Washington Post/ABC poll showing him actually behind Donald Trump, something considered almost unthinkable even before Trump’s indictment in New York three months ago. Biden has two crucial but connected problems — his age and his vice president. Harris’s unpopularity compounds voters’ concerns about Biden’s stamina and even his survival through a new term.

Since Biden shows no sign of willingness to step aside himself, both his low approval ratings and the danger to the country from Trump’s potential return to the White House make it imperative that Biden select a running mate who best enhances his chances for reelection. Obama is the only person who could practically guarantee Biden’s reelection, whose qualifications cannot be disputed, and who could replace Harris without alienating a major constituency.

While the idea of Obama running as Biden’s vice president would, at first, not appeal to either of them, their concern for the good of the country suggests that they should carefully consider this course. When Biden agreed to sign on as Obama’s vice-presidential running mate in 2008, Biden was the veteran with decades of service in the Senate, including chairmanships of both the judiciary and the foreign affairs committees. By contrast, Obama was a junior senator in his first term. But Biden took the subordinate slot. Now, turn-about should be fair play, and Obama should be willing to run in second place along with the incumbent president. Their prior relationship should enable them to come to an acceptable understanding about significant responsibilities for Obama as vice-president.

Faced with the prospect of a career-ending defeat partly of her own making, Harris should accept Obama’s selection, especially if she is assured of some significant post in the new administration, giving her additional time and opportunity to burnish her credentials.

At first blush, the 22nd Amendment might be thought to preclude Obama from being on the 2024 ticket. That amendment provides: “No person shall be elected to the office of the President more than twice …” (emphasis added). While Obama is precluded from ever running again for election as president, the amendment does not prohibit him from running for any other office, including vice-president.

Nor does the last sentence of the 12th Amendment disqualify him. It stipulates that “no person constitutionally ineligible to the office of President shall be eligible to that of Vice-President of the United States” (emphasis added). For several reasons, this requirement does not expand Obama’s inability under the 22nd Amendment to run for election as president.

First, the 22nd Amendment was adopted to address a single, perceived problem — Franklin D. Roosevelt’s decision to run for reelection to a third and then fourth consecutive term as president. Thus, it bars two-term presidents only from being “elected to the office of President.” It says nothing about running for, and being elected to serve, as vice president.

Second, the 12th Amendment regulates voting by members of the Electoral College. The “constitutionally ineligible” clause ensures that the electors may not vote for someone who does not meet the qualifications for the presidency set forth in Article II of the Constitution, which provides only three requirements to be “eligible” to become president: “No person except [i] a natural born citizen … shall be eligible to the office of President; neither shall any person be eligible to that office [ii] who shall not have attained to the age of thirty five years, and [iii] been fourteen years a resident within the United States” (emphasis added).

Despite the fictitious “birther” theories concocted when Obama first ran, Obama meets the three constitutional tests of “eligibility” set forth in Article II — age, native citizenship, and residency. As with the scenario that I propose for Biden and Obama to consider, there are other paths to an Obama return to the presidency that the 22nd Amendment would not bar, thus confirming that he is eligible to run in 2024 for vice president.

For example, a former president is surely entitled to run for Congress, as former president John Quincy Adams did in 1830. Nothing in the Constitution would prevent such a senior statesman from being selected as Speaker of the House. Reflecting the status of the Speaker in the line of presidential succession since 1792, the Presidential Succession Act of 1947 makes the Speaker second in line to replace a president who dies in office. If both the president and the vice president were to die, the 22nd Amendment would not block a former president then serving as Speaker from succeeding to the Oval Office again.

Similarly, a person in Obama’s position would be “eligible” for nomination to fill a vacancy in the office of vice president under the 25th Amendment, which contains open-ended authorization to select a vice president. Whenever there is a vacancy in the office of the vice president, “the President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress.” Nothing suggests that a former two-term president would not be an otherwise “eligible” candidate for the vice presidency in such a process.

One obvious concern, of course, is whether this election ticket would survive an inevitable challenge from an unsuccessful Republic candidate, whether Donald Trump or someone else. As the 2020 election showed, part of the Republican campaign strategy is to contest any results that are unfavorable. Would a Supreme Court dominated by conservative justices appointed by Republican presidents invalidate the certification of a Biden/Obama win or even allow states to exclude this slate from the ballot?

For a couple of reasons, the Supreme Court should not be a problem. There are good arguments that this is the kind of “political question” that the Constitution commits to a separate branch, specifically the outgoing vice president and Congress in accepting and counting the certified results of the electors in each State. That should have been settled on Jan. 6.

But if the court were to reach the merits, both precedent and ideology would sustain the validity of the ticket (and would prevent individual states from excluding a Biden/Obama ticket from the ballot). In the most apt precedent, involving the attempt by the House of Representatives to refuse to seat a controversial New York congressman, Adam Clayton Powell, the Supreme Court ruled that “the House could exclude him only if it found he failed to meet the standing requirements of age, citizenship, and residence contained in Art. I, § 2, of the Constitution.” As discussed above, those are precisely the only three types of qualification that the Constitution establishes for the presidency and vice presidency.

Furthermore, the current conservative majority consists of “textualists” as defined by the Federalist Society, to which they all owe allegiance: “A textualist endeavors to give effect to the words of the Constitution and statutes. If the meaning of the words is clear, the judge goes no further.” Nothing in the constitutional text bars Obama from running for vice president or, if circumstances required, succeeding to the presidency.

Thus, Obama would be a constitutionally-eligible vice presidential candidate for the 2024 race. And a Biden-Obama ticket? The idea is not as crazy as it sounds at first — although the former president, enjoying his life as a private citizen, might not be crazy about the idea.

Philip Allen Lacovara has served as Deputy Solicitor General of the United States, counsel to the Watergate special prosecutor, and president of the District of Columbia Bar.