James Talarico barely mentioned Donald Trump when he finally got to give his victory speech on Wednesday night as Democrats’ nominee for U.S. Senate in Texas. But the 36-year-old state lawmaker is now a front man for the left’s opposition to Trump, not just in his own state but around the country. With his victory over U.S. Rep. Jasmine Crockett, the state lawmaker from Austin will test whether a smiling message of unity and change is enough to answer voters’ frustrations amid discord at home and now a war abroad. “We’re done being divided. We’re done being played,” Talarico said,...