Democratic presidential candidate Sen. Bernie Sanders (I-VT) is joined by his family on stage during a rally with at the Champlain Valley Expo March 03, 2020 in Essex Junction, Vermont.

Bernie Sanders thinks Joe Biden is a "decent guy." He just believes the only person now capable of denying him the 2020 Democratic presidential nomination is wrong about, well, a lot of things.

After the Super Tuesday primary results set the Vermont senator and former vice president on a collision course in the race to take on President Donald Trump, Sanders contended Wednesday that Biden had much to "explain" to American voters. From trade deals to the Iraq War, the health-care system and the social safety net, Sanders aimed to draw distinctions between his record and Biden's.

He framed the next phase of the Democratic primary as a fundamental question of, "which side are you on?" He cast Biden as beholden to billionaire donors, questioning whether a candidate backed by the "corporate world" would bring about changes working families "desperately need."

"The American people have got to understand that this is a conflict about ideas, about a record, about a vision for where we go forward," he told reporters at his Vermont campaign headquarters. He insisted he does not want the campaign to "denigrate into a Trump-type effort" riddled with "personal attacks."

Welcome to the new Democratic primary, the result of a whirlwind few days where Biden swiftly stacked up support as centrist alternatives to him fell to the wayside. As a two-person race develops, Biden has cast Sanders' sweeping proposals as too much of a risk for a party that has one chance to deny Trump a second term in the White House.

Biden leapfrogged Sanders for the pledged delegate lead on Tuesday as he dominated in the South and won key states such as Texas, Massachusetts and Minnesota, according to NBC projections. Sanders kept pace by racking up an early delegate lead in California, though the most populous U.S. state's primary was still too early to call Wednesday afternoon.

Biden held an overall 513 to 461 pledged delegate lead as remaining results trickled in Wednesday, according to NBC News.