George Washington didn’t have a nominating convention. As the commander of the colonial forces in the American Revolution, he was an easy candidate to select from among the eligible pool of any white man 35 and older, and he won his first two elections without any real competition. After that, there was no clear path for narrowing the pool, so political parties developed their own ways of choosing candidates.

Parties began holding conventions in the early 19th century and presidential primaries in the early 20th century. The convention remained the main way of selecting candidates until 1972, when new rules gave the primaries more power to determine the nominee. Since then, conventions have become a way to celebrate a predetermined candidate, rather than a means of choosing one.

Once Washington said he wouldn’t run for a third term, congressmen began choosing their parties’ nominee in private caucuses. Critics derided the system as “King Caucus,” and in September 1831, the Anti-Masonic Party held the first national presidential-nominating convention as an alternative to the caucus. Later that year, the National Republican Party (a different party than the modern Republican Party) held its own convention.

The major shift came in 1832, when sitting president Andrew Jackson decided that his party, the Democratic Party, should hold a convention, too. Although Jackson tried to portray this as a way of giving voters more power, historian Jill Lepore suggests in The New Yorker that it was actually an attempt to replace Vice President John C. Calhoun with Martin Van Buren on the ticket. (Jackson succeeded and won reelection.)

Since then, every major party, with the exception of the Whigs in 1836, has held a national convention to nominate its presidential candidate. Still, nominating conventions in the 19th century were very different from the versions Americans watch on TV today. Back then, the winning candidate didn’t give an acceptance speech or even necessarily attend the convention—an unofficial practice that ended with Franklin D. Roosevelt in 1932.

“Throughout most of the 19th century, campaigning was kind of considered uncouth,” says Stan M. Haynes, a lawyer in Baltimore and author of two books on the history of U.S. nominating conventions.

“Candidates would write letters and do things behind the scenes, but to do anything publicly to show that you were running for president was kind of considered to be tacky,” he continues. “The party should come to you, you should not come to the party.”

One of the other big differences between modern conventions and 19th-century ones is that there were no presidential primary elections. The convention was when candidates were selected. As with the caucus before it, party members eventually came to see this as an undemocratic system in need of reform.

Early 20th-century politicians advocated for primaries by saying they’d make the nominating process more democratic, even if that wasn’t always politicians’ main reason for supporting them. In 1912, former president Theodore Roosevelt—who’d previously opposed primaries—publicly supported them when he realized it might be the only way to wrest the Republican Party nomination from the sitting president (and his former secretary of war) William Howard Taft.

Only 13 of the 48 states held Republican primaries in the 1912 election, so although Roosevelt won most of the races, he didn’t secure enough delegates to win the nomination. He responded by breaking from the Republicans and starting the Progressive Party or “Bull Moose Party” so he could run for president on its ticket. The new party’s nominating process, however, was deeply undemocratic: the Progressive convention refused to seat Black delegates, including those who’d supported Roosevelt at the Republican convention.

Even as more states began to hold primary races over the next few decades, the convention remained the main way of selecting a candidate for president. Adlai Stevenson didn’t run in any of the 1952 Democratic presidential primaries, but still won the convention’s nomination that year. His Republican opponent, Dwight Eisenhower, wasn’t a clear winner in the Republican primaries, but the convention selected him because he led in opinion polls.

“The effect of primaries was not that they would elect enough delegates to make the decision,” says Geoffrey Cowan, a professor of communication and journalism at USC Annenberg School and author of Let the People Rule: Theodore Roosevelt and the Birth of the Presidential Primary.

“Instead of that, they were testing grounds for people’s popularity,” he continues. Primaries played a significant role in selecting John F. Kennedy as the 1960 Democratic presidential nominee. “It was thought that a Catholic couldn’t win the presidency, and when he won the state of West Virginia…it showed that he could win.”

Between the 1968 and 1972 presidential elections, the balance of power between the convention and the primaries radically shifted, giving primaries far more power in picking candidates.

The 1968 Democratic National Convention in Chicago is one of the most significant party conventions in U.S. history. Outside, police and military forces attacked and arrested hundreds of anti-war protestors (this would become the “riot” at the center of the Chicago Eight trial). Inside, party leaders ignored primary results supporting anti-war candidates like Eugene McCarthy and instead nominated Vice President Hubert Humphrey, a Vietnam War supporter who hadn’t run in the primaries.

Cowan, then a law student who’d worked for McCarthy’s campaign, organized the Commission on the Democratic Selection of Presidential Nominees to consider whether the party needed to change its rules. This led the Democratic Party to adopt new rules giving more power to primary elections in selecting a presidential nominee. The Republican Party followed suit by rewriting its rules in a similar way.

Though both parties have made changes (such as “superdelegates”) to their rules since then, the fundamental shift toward primaries as the most important way of selecting a candidate has remained.

Subsequent attempts to challenge primary winners at conventions have been unsuccessful. In 1976, future president Ronald Reagan failed to win the Republican nomination over primary leader Gerald Ford. During the next presidential election, Ted Kennedy—who was convicted of leaving the scene of the accident that killed Mary Jo Kopechne—also failed to wrest the nomination from Jimmy Carter, the clear primary winner.

Since those attempts, Democratic and Republican conventions have simply provided a venue to celebrate and promote a chosen candidate, rather than pick one. It’s a much different kind of process than it was in 1880, when James A. Garfield gave a convention speech endorsing John Sherman as the Republican nominee. The delegates liked him so much they nominated Garfield, not the person he endorsed, and Garfield went on to be president—an unthinkable outcome in 2020, when major party conventions are predetermined and largely remote due to the COVID-19 pandemic.