Former President Obama hasn’t tipped his hand about a favorite in the 2020 Democratic fight. But Deval Patrick’s entry into the primary race makes life more difficult for Joe Biden, who frequently tries to portray himself as the second coming of his friend “Barack.”

Patrick, the Massachusetts governor from 2007 to 2015, is personally close with Obama. The Harvard Law School graduates, who were introduced by a mutual acquaintance in the 1990s when Obama was running for state Senate in Illinois. Patrick, 63, was elected only the nation’s second black state chief executive two years before Obama made history as America’s first African American president. And they share a brand of practical, progressive politics, liberal in their outlook but conditioned to working within the political system.