Yesterday, I noted that Senator Bernie Sanders has a very high net favorability rating, which would be unlikely to last through a general-election campaign. Another way the polls may be overstating his strength: They reflect a high level of support from young Americans, who may not show up to vote. To be as electable as a more moderate Democrat, two political scientists have estimated, Sanders “would have to boost youth turnout far above historical levels.”

Ramesh Ponnuru is a senior editor for National Review , a columnist for Bloomberg Opinion, a visiting fellow at the American Enterprise Institute, and a senior fellow at the National Review Institute. @rameshponnuru