Tens of thousands of ballots have been rejected in key battleground states, where the outcome in November for the presidency and other races could be determined by a small number of votes.

Joe Biden formally accepted the Democratic Party's nomination for president on Thursday, Day 4 of the convention. NPR reporters provided live analysis of his remarks.

Kamala Harris used her prime-time speech to introduce herself and excoriate President Trump. Former President Barack Obama launched a rare attack on his successor. And Democrats urged people to vote.

Harris formally became the Democratic Party's vice presidential candidate and Joe Biden's running mate on Wednesday. Watch her remarks to the DNC.

Obama said democracy is at stake in a blistering attack of President Trump, urging Americans to vote for Joe Biden in November: "Don't let them take away your power." Watch his remarks.

He voted by mail in Tuesday's Florida primaries but avoided the Postal Service, instead opting to give his ballot to a third party to turn in, a practice Republicans call "ballot harvesting."

Tuesday's lineup featured Jill Biden, who gave personal and hopeful remarks. Other speakers Tuesday touted health care, and a remote roll call vote featured diverse voices.

Sen. Kamala Harris accepts the Democratic vice presidential nomination on Wednesday. Her education at a historically Black university seen as the center of Black intellectual life helped pave the way.

Former first lady Michelle Obama stole the show as Democrats tried out a glossy, highly produced, made-for-TV special to replace the energy of a live crowd at a convention.

In remarks Monday night, Vermont Sen. Bernie Sanders called for an "unprecedented response" to defeat President Trump and elect Joe Biden.

The former first lady used her prime-time speech during the opening night of the Democratic convention to rebuke President Trump and urge Americans to vote for Biden "like our lives depend on it."

"The future of our democracy is at stake. The future of our economy is at stake. The future of our planet is at stake," Sanders said of this year's presidential election.

"So let me be as honest and clear as I possibly can. Donald Trump is the wrong president for our country," the former first lady said Monday night.

Follow NPR's special coverage of the DNC beginning Monday at 9 p.m. ET. The program includes Vermont Sen. Bernie Sanders and former first lady Michelle Obama.

Despite the booming stock market under President Trump, the finance sector is giving a bit more money to Democrats than to Republicans for the first time in more than a decade.