Is the Democratic Party making a mistake by renominating President Biden to face the likely Republican nominee, Donald Trump, in 2024? A nontrivial number of voices in and outside the party seem to think so.But it’s already a mostly moot point. The system Americans use to nominate presidential candidates is not well equipped to make swift strategic adjustments. Voters choose candidates in a sequence of state-level primaries and caucuses. Those contests select delegates and instruct them on how to vote at a nominating convention. It’s an ungainly and convoluted process, and politicians begin positioning themselves a year in advance to succeed in it.It wasn’t always this way, and it doesn’t have to be. Political parties in most democracies have the power to choose their leaders without going through a monthslong gantlet.The best way for a party to choose its leader is for that party to convene, confer and compromise on a candidate who serves its agenda and appeals to voters. The conventions of the mid-20th century, deeply flawed as they were, were designed for that purpose. If those flaws were fixed, they would be far better than what we use today.Should Mr. Biden run again or step aside? On the one hand, he has stubbornly low approval ratings, and a number of polls show him trailing Mr. Trump. On the other hand, polling a year out is often misleading, and so are job approval ratings in a polarized age. Mr. Biden is old, but so is Mr. Trump, and Mr. Biden defeated him last time.Replacing an incumbent president with another nominee is very rare and probably should be. But a convention could do it if necessary. In 1968, President Lyndon Johnson stepped down at the beginning of the year, and Democrats could realistically expect to find a nominee before Election Day.The system was different then. When Mr. Johnson decided not to run for re-election, he declared, “I shall not seek, and I will not accept the nomination of my party for another term as your president.”The “and I will not accept” matters. Mr. Johnson was acknowledging that the party might nominate him even if he didn’t run. In 1968, when the decision was made at the national convention, the party could do that. That’s not something it can easily do today.Only a small fraction of states held primaries that year, and most of those didn’t commit delegates. Primaries were a tool to gauge public support, not make the final decision. Hubert Humphrey, the eventual nominee, won no primaries or caucuses. Instead, he won with support of unpledged delegates selected through state conventions — delegates who represented an older, more establishment part of the party.The apparent injustice of Mr. Humphrey winning the nomination without winning primaries was a big part of how we got to our current system. Many members of the Democratic Party felt that their perspectives weren’t well represented by those establishment delegates; their voices were being heard in the primaries and caucuses.The party set out to create a national convention that was more representative of the party, but what evolved was something else, the system we use today — the one that has all but locked us into a candidate almost a year out from Election Day.Early states winnow the field. The next states largely determine who the nominee is. States that vote late in the process often have little effect. Success depends on the ability to stand up a campaign in state after state in the first few months of the year, which in turn depends on the ability to raise money and attract media attention. It’s a process, not a simple decision.This system could produce a candidate who is battle tested by the primaries and otherwise broadly popular. It might also select a candidate who appeals narrowly to a group of dedicated followers, especially in early states, where a close victory can be leveraged into later success. (Think of Mr. Trump in 2016.)In no way does it let party leaders take stock of an awkward situation, such as what Democrats face now (low approval ratings for an incumbent) or, for that matter, what Republicans face (a front-runner facing multiple indictments).Party leaders are not completely helpless. In “The Party Decides,” the political scientists Marty Cohen, David Karol and John Zaller and I argued that party activists and leaders could exert a lot of influence on their party’s choice — so much so that they typically get their way. When they can agree on a satisfactory candidate, they can help direct resources to that candidate and help that person stay in the race if he or she stumbles. (Think of Mr. Biden in 2020.)But that takes time. It is, at best, a blunt instrument (hence its failure among Republicans in 2016). The nomination is still won in the primaries, and an incumbent is especially hard to replace.Most democracies give far less power than that to a single political leader, even an incumbent or influential former leader. Healthy parties can limit their leaders.Empowering the Democrats to replace Mr. Biden or the Republicans to move on from Mr. Trump would come with costs. A party that could persuade a sitting president to stand down would also have the power to persuade outsiders, like Bernie Sanders and Mr. Trump, to not run at all.For some, giving party leaders this kind of influence is unsettling. It shouldn’t be. The job of choosing a nominee is complicated. It involves the strategic trade-off between what kind of candidate can win in November and what kind of candidate represents what the party wants in a leader.Letting the party make these decisions is not inherently undemocratic. Just as voters select members of Congress, who then gain expertise, forge compromises and bargain to make policy, so too could voters select party delegates, who would then choose nominees and shape their party’s platform.Polling and even primaries could continue to play a role. In many years, the voice of the party’s voters might speak loudly, and party leaders would simply heed it. In other years, such as for Democrats in 2008, voter preferences might be more mixed. It’s worth noting that in 2008, Democratic superdelegates (those not bound by the results of any primary) switched their support from Hillary Clinton to Barack Obama after seeing his appeal in the primaries. If all of the delegates had been free to switch, would the outcome have been the same? We don’t know, but in a representative democracy, elected representatives do often listen to voters.In other words, the development of a more active, empowered party convention would not have to be a return to the past. The nomination of Mr. Humphrey in 1968 was a problem, but it wasn’t because the decision was made at a convention. It was because the delegates at that convention didn’t represent the party’s voters.Moving the decision back to the convention would not be a trivial matter. Even if voters and politicians could adjust to the change — a big if — each party would need to select representative and competent delegates. Our experience with representative democracy should tell us that this is possible but far from inevitable.But such a convention would still be superior to the current system, in which a small number of voters in a handful of states choose from a pool of self-selected candidates who have been tested mostly by their ability to raise money and get attention in debates.Both of these systems have a claim to being democratic. But only the first would give the party the kind of agency implied by claims that it is making a mistake by renominating the incumbent.Hans Noel, an associate professor of government at Georgetown, is the author of “Political Ideologies and Political Parties in America” and a co-author of “Political Parties” and “The Party Decides: Presidential Nominations Before and After Reform.”Source images by Drew Angerer, Rost-9D, and ajt/Getty ImagesThe Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.Follow the New York Times Opinion section on Facebook, Instagram, TikTok, X and Threads. More