Former Vice President Joe Biden scored sweeping victories on Tuesday, winning at least four of the six states holding contests in the race to select the Democratic nominee who will take on Republican President Donald Trump in the November election.Biden and Senator Bernie Sanders of Vermont are in a two-way battle for the party's nod. A candidate needs at least 1,991 delegates to secure the nomination, and Biden led the delegate count heading into Tuesday's contests. At stake on Tuesday were 352 delegates. Based on partial results as of Wednesday morning, Biden has won at least 158 delegates and Sanders at least 100, according to Edison Research.Here is a quick look at the state of play:MICHIGANDelegate count: 125The biggest prize on Tuesday, Michigan delivered a crucial victory for Biden. He will secure at least 53 delegates and Sanders at least 39 delegates.Both campaigned hard in the state, where Sanders had pulled off a stunning upset over eventual nominee Hillary Clinton in the 2016 Democratic primary.WASHINGTON STATEDelegate count: 89With an estimated two-thirds of the vote counted in Washington, Sanders and Biden were tied at 33% each. They will both secure at least 27 delegates.Sanders cruised to victory in this liberal-leaning state in 2016. But a surging Biden appeared to have closed the gap, even though Sanders had a far bigger presence on the ground.Washington switched this year from holding caucuses - a format that has historically helped Sanders by drawing a younger, more activist electorate - to a primary election in which voters cast their ballots by mail. The mail system makes the vote tallying process stretch for days and could delay knowing the winner until later in the week.MISSOURIDelegate count: 68Biden won Missouri and will secure at least 32 delegates. Sanders will win at least 18 delegates.While neither campaign made a major investment in Missouri, Biden's support from black voters helped propel him to victory in the state. Sanders lost Missouri by a tiny margin to Clinton in 2016.MISSISSIPPIDelegate count: 36Biden won Mississippi and will secure at least 30 delegates.Biden was the clear favorite in Mississippi, given his strength among African American voters and his dominant performance last week in neighboring Alabama. In 2016, more than two-thirds of Democratic primary voters in Mississippi were African American.IDAHODelegate count: 20Biden won Idaho and will get at least 10 delegates, while Sanders will secure at least eight. Sanders easily won the state in 2016, but its shift to a primary from caucuses may have hurt his chances this time round.NORTH DAKOTADelegate count: 14Sanders won North Dakota and will collect eight delegates, with Biden receiving the remaining six. Like Idaho, North Dakota strongly backed Sanders in 2016.DEMOCRATS ABROADDelegate count: 13New in 2020, this global primary allows Democrats living abroad, including many who relocated permanently or work for the U.S. State Department, to participate in voting that ended on Tuesday. Democrats could either vote at hundreds of voting centers around the world between March 3 and Tuesday, or send in ballots by midnight PST (0700 GMT on Wednesday).