President Joe Biden is widening a critical window for low-income Americans to join Obamacare‚ in a move aimed at reinforcing a central element of his reelection bid: That he presided over a historic expansion of health care coverage. Tens of millions of people eliminated from Medicaid would now have until Nov. 30 to sign up for new coverage under a plan to be announced Thursday by the Department of Health and Human Services and first shared with POLITICO — an extension from the July 31...