Former Vice President Joe Biden will run for president in 2020, a senior Democratic lawmaker told The Hill on Tuesday, a move that will shake up the crowded Democratic primary field and make him the clear front-runner for his party’s nomination against President Trump. “I’m giving it a shot,” Biden said matter-of-factly during a phone call with a House Democratic lawmaker within the past week — a conversation the congressman recounted to The Hill and interpreted as a sure sign that Biden will run in 2020. In the brief phone call, the former vice president asked if he could bounce...