A longstanding American tradition kicks off on Monday as the country’s two major political parties begin the formal presidential nomination process.

The Democrats were scheduled to meet in Milwaukee in July, but the pandemic prompted a delay and then a switch to an all-virtual event. Delegates and party leaders will meet online for four days with former Vice President Joe Biden scheduled to accept the nomination Thursday.

Then it’ll be President Donald Trump and the Republicans’ turn. The party is still planning to have 300-plus delegates meet in-person to formally nominate the president, but the public and most press will have virtual access.

Given that the nominees are already decided months before anyone steps foot in a convention hall, why do the political parties still have conventions?

“They can be kind of long and drawn out and boring to watch at times,” said William Howell, a political science professor at the University of Chicago and head of the Center for Effective Government.

“The conventions have served just as a kind of coronation,” Howell said. “But that’s not to say that they don’t serve any function whatsoever. They do serve some functions and some functions that one could argue are healthy for our democracy.”

Function #1: Business and advertising

The two major conventions are broadcast on national television in prime time. It’s a chance for the parties to show off their candidate and talk about what they stand for as Democrats or Republicans.

“It’s three or four days of nonstop advertising,” Howell said. “And look, in a world in which most citizens pay little attention to politics that isn’t, obviously, bad, right? That we kind of stop and pause and say, ‘Alright Republican Party, alright Democratic Party. What are you about?’ ”

But there is actual important business to do, said Mary Morrissey, executive director of the Illinois Democratic Party. Legally, the delegates have to formally nominate the candidates and approve the official party platform. There are also a number of smaller groups, like the women’s caucus and the interfaith council, who will meet to discuss organizing, policy and other issues.

Morrissey said moving to a virtual event is important for public health. She also said it is nice that people can attend the event from anywhere.

“It’s almost an opportunity to be more inclusive, rather than just those people who got on the ballot and got elected as delegates,” Morrissey said.

Function #2: A party for Party unity

The national political conventions mark an important shift in election season, away from primaries and caucuses toward the general election.

“It’s a rare chance to be able to see and interface with members of Congress, Senators, congressmen and party leaders and celebrities. It’s just a big party, a mecca for the democrats every four years,” said political strategist Becky Carroll, who runs her own firm C-Strategies.

“We all know it’s very different being at a Cubs game, watching it in Wrigley Field with a beer in your hand and a hot dog versus watching it at home, right?” she noted.

Carroll has been to four conventions and said it’s an important place to network, And for politicians, it can launch careers. Take, for instance, President Barack Obama’s 2004 speech at the Democratic National Convention in Boston.

“I remember looking around the convention hall, and literally every person sitting in those seats [was] glued to every word that Senator Obama was saying, and you just felt at that moment in time that that was something very special,” Carroll said.

Christopher Dunn has been to more than a dozen conventions and has the stories to prove it. His first was the 1976 Democratic National Convention in New York when Jimmy Carter was accepting the nomination.

“I got to do some really cool stuff, like go to parties in a small hotel suite with Paul Newman and Warren Beatty,” Dunn said.

Function #3: Fundraising

While there are many ways both parties fundraise, the conventions bring in money. People buy box seats. They pay for tickets to exclusive parties.

Take the 1988 DNC, when Dunn says he was helping big donors get floor passes and backstage access.

“I remember some of the most important donors coming to me and saying, ‘Do you know who I am, Chris? You know who I am. I need to be on the floor.’ And I would say, ‘I want you to be on the floor. Let me see what I can do.’ ”

All that’s gone this year. But Dunn says it’s another reason conventions will most certainly be back.

Political strategist Jason McGrath says just like parties, weddings and graduations will happen post-pandemic, so too will the conventions. And like sports, they thrive on live audiences.

He says President Donald Trump is a good example.

“The Trump campaign: I think they were highly successful in building support and energy for their campaign in 2016 through these rallies,” McGrath said. “The absence of that, I think, is really a problem for them.”

McGrath is bummed he won’t get to see his fellow Democrats and friends from other states who work on other campaigns this year.

“I do think that there will be a yearning to come together again, to celebrate our party and to really appreciate what we have after so much that we would have gone through together, given the pandemic, given the unrest facing our country,” Carroll said.

She predicts the 2024 conventions will be back in a big way.

Becky Vevea covers City Hall for WBEZ. Follow her @beckyvevea.