When Amanda Berg heard reports that President Donald Trump mocked the accents of the leaders of South Korea and Japan at a recent fundraiser, it brought back painful memories from her childhood. Berg, a Korean American who grew up in Fort Collins, Colorado, recalled kids doing the “stereotypical pulling at the eyes and the mocking accent.” It made her feel like she was a foreigner in her own community. Berg, a registered Democrat, is among a growing and crucial bloc of Asian American voters leaning further to the left in the age of Trump, and his stunt, reported by the...