Primary Day: Biden hopes to finalize delegate deal, with eyes on outcome of extended mail-in voting

Voters return to the polls Tuesday as nine states and the District of Columbia hold primary elections in which Democratic presidential candidate Joe Biden is expected to gather enough delegates to secure the party nomination, in what is expected to be largely mail-in voting that could be a test case for November.

Biden has 1,566 delegates as the polls open and needs 1,991 to secure the nomination.

The marque contests will be the Massachusetts Senate Democratic primary between incumbent Sen. Ed Markey and challenger Rep. Joe Kennedy and Iowa's 4th congressional district, in which controversial GOP Rep. Steve King is trying to keep his seat.

King recently had his committee assignments taken away after he appeared to defend the phrases "white supremacy" and "white nationalism" in a New York Times interview. He is being challenged by Republican state Senator Randy Feenstra, who has earned support from the U.S. Chamber of Commerce and other mainstream GOP groups. 

There are several other Republicans on the ballot against King, running the risk of splitting the anti-King vote and handing the nomination to the internally unpopular congressman.

Idaho, Indiana, Iowa, Maryland, Montana, New Mexico, Pennsylvania, Rhode Island, South Dakota and Washington, D.C. are voting Tuesday, as the nation moves into a second week of protest and racial unrest over the death of George Floyd after being arrested by Minneapolis police. 

Several cities in which voters are going to polling stations have officially imposed curfews. D.C. Mayor Muriel Bowser has said that voters will be exempted from the city's 7 p.m. Tuesday night curfew.

It is unclear how the continued protests against police brutality will interfere with voting.

In the biggest election night since Super Tuesday, the voting today could serve as a test case for the concept of widely expanded mail-in ballots. Due to the coronavirus pandemic, Pennsylvania, Iowa, Indiana and New Mexico have increased the ability of voters to cast their ballots remotely.

Democrats have embraced the practice more than Republicans, which could in large part be due to President Trump's repeated argument that extended mail-in voting yields higher rates of voter fraud.

Exit polls showing a majority of mail-in voters being Democrats could be a strong indication that the GOP's position on such balloting is backfiring. 

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