Joe Biden calls for labor secretary Acosta to resign; Top Dems call for labor secretary Alex Acosta to resign for role in cutting "deal of a lifetime" for Jeffrey Epstein; Bill Clinton statement: "knows nothing" of alleged Epstein crimes; Biden on Obamacare: starting over would be a "sin"; Biden fiercely defends Obamacare as rivals call to replace it; Harris struggles to clarify "Medicare for all" stance; Biden releases tax returns, made $15M+ since leaving WH; Sen Kaine: Trump should feel badly for victims "preyed upon"; Sen. Tim Kaine: Acosta must go; Trump steps up attacks on U.K. Ambassador to U.S., calling him "wacky" and a "very stupid guy"; Politico: Trump admin members known to party with U.K. Ambassador who Trump now calls "wacky"; Senior British leaders defending Ambassador attacked by Trump; State Dept: no WH guidance to cut ties with U.K. Ambassador; Billionaire who shook up two presidential races dies at 89 via Knit