Joe Biden notched major victories in at least four of Tuesday's six primaries, winning by wide margins over Bernie Sanders in Michigan, Mississippi, Missouri, and Idaho. The results in Washington state and North Dakota were too close to call by early morning, but the former vice president appeared to be amassing a formidable lead over the Vermont senator.

Biden's support among African-American voters and suburban women were behind the results in Mississippi, where he racked up over 80 percent of the primary vote; in Michigan, where he won by 13 percent over Sanders, who took the state against Hillary Clinton in 2016; and in Missouri, where he beat Sanders by over 26 percent.

Those wins left Biden with an estimated 785 delegates and Sanders with 645 delegates, according to the Washington Post — potentially an insurmountable lead.

Sanders went home to Burlington, VT, on Tuesday evening and did not speak to his supporters after the polls closed. He and Biden had both canceled large primary night rallies in Cleveland at the request of Ohio's governor due to the coronavirus infection. The former vice president, accompanied by Dr. Jill Biden, delivered a brief address to a small crowd of supporters in Philadelphia.