Hasan Piker's emergence as a Democratic campaign surrogate has split the party between those who see him as a crucial bridge to millions of young voters and those who view his inflammatory rhetoric as a liability that could cost elections. When Abdul El-Sayed, a Democratic Senate candidate in Michigan, announced this week that Piker, a far-left Twitch streamer, would appear at campaign rallies next month, the conflict inside Democratic ranks erupted. The decision drew immediate fire from El-Sayed's primary opponents and national Democratic figures, forcing a rare public reckoning over how far the party should go to recapture young men...