Kamala Harris’ most notable foray into health care policy was when she endorsed an idea she now says she doesn’t support. In 2017, she co-sponsored a single-payer health care plan developed by Sen. Bernie Sanders (I–Vt.). That plan would have cost about $30 trillion, by many estimates, and would have eliminated virtually all private insurance, replacing it with a single government-financed plan. When Harris campaigned for the Democratic presidential nomination in early 2019, she initially proposed a plan along those lines and gave interviews backing the elimination of current private health in…