Is Vermont Democratic Sen. Bernie Sanders electable? As Sanders has surged in the polls, supporters of former Secretary of State Hillary Clinton are issuing increasingly dire warnings about his general election prospects. On websites like Vox, many political scientists agree: He can't win. Millions of dollars in Republican ads, they insist, will paint him a socialist or a red. Americans aren't about to elect a Jewish socialist who still hasn't lost his Brooklyn accent.

It will be a debacle, critics predict, like Democratic Sen. George McGovern's crushing 1972 loss, when the Democrats lost 48 states, or Republican Sen. Barry Goldwater, buried by President Lyndon B. Johnson's stunning landslide in 1964. It will set progressives back for decades.

Ironically, as Sanders rises in the polls and does better than expected, the alarms grow in volume and intensity. It verges on oxymoronic for Clinton and the party establishment to scorn as unelectable a candidate who is beating her at the ballot box.