Why don't we know which Democratic candidate can beat Trump?

Can a woman beat Mr. Trump?

Women have driven Democrats’ electoral victories, but many Democratic voters are nevertheless convinced a woman can’t beat Mr. Trump. Story after story documents Democratic voters — men and women alike — expressing the view that a woman can’t win. This may explain the lackluster to poor results so far for Senator Elizabeth Warren of Massachusetts. Yet by multiple measures, she is broadly liked by Democratic voters, second only to Mr. Biden in the Economist’s measure of who voters are considering. Her marquee policy position, a two-cent wealth tax on incomes over $50 million, polls at 63 percent, including 55 percent support from independents and 57 percent support from Republicans.

Women have powered the resistance to Mr. Trump: The Women’s March was likely the biggest protest event in American history, and increased support from women drove a “blue wave” in the 2018 midterms. And in many elections, women candidates outperformed men: Among Democrats, “female candidates in 2018 are more likely to defeat male candidates than the other way around,” reports Ella Nilsen of Vox.