Lobbying, revelry and even the traditional balloon drop are off the menu at the 2020 U.S. party conventions, which begin on Monday with a Democratic event delayed by the COVID-19 pandemic.

Joe Biden will accept his party's nomination for the U.S. presidency on Thursday, the final day of a Democratic National Convention that Republican rival Donald Trump will attempt to distract from with a series of swing-state appearances and a multi-million-dollar ad buy.

The four-day Democratic convention, originally planned for the key battleground state of Wisconsin, will include a series of remote appearances from the party's biggest names as well as up-and-coming political stars, musicians and celebrities in a made-for-TV special.

Obamas, Clintons and Legend

Traditional-style speeches are expected to be limited, with participants speaking either in pre-recorded clips or via video link from their chosen locations across the United States as part of four two-hour television broadcasts in primetime.

Former presidents Barack Obama and Bill Clinton will be among the virtual speakers, along with progressive leading lights Bernie Sanders, Elizabeth Warren and Alexandria Ocasio-Cortez.

While Biden has so far managed to paper over divides in the party that spilled out following Hillary Clinton's nomination in 2016, there has reportedly been disquiet from the progressive wing that 30-year-old Ocasio-Cortez has been allotted just 60 seconds to speak while a platform has been offered to John Kasich, the former Republican governor and Trump critic. 

Seventeen rising party stars will together give the keynote address – a slot which propelled Obama into the national spotlight in 2004 – on Tuesday. Many of the women reportedly considered by Biden as his running mate are also on the bill, with Kamala Harris, his eventual choice, scheduled to speak on Wednesday evening.

Musicians slated to deliver online performances include John Legend, Jennifer Hudson and Billie Eilish, and the convention will conclude with Biden accepting the Democratic nomination on Thursday.

Party hopes for polling, donor boosts

Conventions are traditionally opportunities for making contacts, approving policy platforms and raising money as well as the nomination of the presidential candidate – in front of thousands of cheering supporters.

Some party business will still take place in Milwaukee, the original location of the convention, but both Biden and Harris will make their addresses in near-empty rooms from the Chase Center in Wilmington, Delaware.

The state-by-state nominating roll call, in which a representative of each state's delegation announces how many delegates it is pledging to each candidate, will take place via video link, ahead of Biden's acceptance speech on Thursday.

Read more:

Graphics: Following the money in the 2020 campaigns

Biden picks Harris: What does it mean for the election?

Presidential candidates typically receive a polling bounce from a convention – Hillary Clinton extended her pre-election lead by three to four points in three polls after she accepted the Democratic nomination in Philadelphia in 2016 – though any uptick can be short-lived.

Biden is already riding high in the polls, but the 77-year-old will be hoping to consolidate his lead ahead of the Republican convention – plans for which are still in flux – on August 24-27. 

An analysis of state-by-state polling averages suggests the former vice president would win the Electoral College by 337-201 if the election were held today, but there is also evidence of a slight narrowing in some states as Trump gains ground on the Democrat.

The convention is also an opportunity to swell the campaign coffers, with major fundraising drives likely throughout the week. 

Trump's distraction plan

The Trump campaign has extensive plans to distract from the Democratic convention, with a series of swing state appearances by the president and a multi-million-dollar digital ad buy.

Trump is scheduled to visit Wisconsin, a state he unexpectedly won in 2016, on Monday in an attempt to draw attention away from the opening of the flagship Democratic event before trips to battlegrounds, including Minnesota and Arizona.

Politico reported that the 74-year-old would deliver a speech near Biden's hometown of Scranton, Pennsylvania – also a key swing state – on Thursday, the day the former vice president accepts the Democratic nomination.

It's unclear whether the death of Robert Trump, the president's younger brother, on Saturday will result in a change of plans.

The Trump campaign team is also planning a multi-million-dollar digital advertising buy during the convention, the New York Times reported on Saturday, including taking over the banner ad on YouTube for 96 hours from Tuesday.

Banner ads have also been purchased on the websites of the Washington Post, the Wall Street Journal, and Fox News, according to the newspaper, and further campaign ads will show in swing states on video-streaming platform Hulu.