evidence: When former Vice President Joseph Biden Jr. becomes the Democratic Party's official nominee for president on Thursday, he will complete two historic and improbable comebacks. [...] But 2020 was far from the first time Biden bid for the White House. His nomination realizes the dream of a recurrent campaign first launched more than three decades ago — in another political era, in another century. No other major party nominee has reached this plateau so many years after their first formal candidacy. [...] This is also a more progressive Democratic Party, as shown by the success of Sanders' two campaigns and the popularity of Warren's stands in 2020. Ideologically, Biden has been generally moderate to center-left, and while he has moved toward Sanders and Warren on health care and other issues since becoming the presumptive nominee, big differences remain.