The headline-grabbing Democratic infighting between Speaker Nancy Pelosi and the high-profile progressive Rep. Alexandria Ocasio-Cortez (AOC), D-New York, must be bringing joy to President Donald Trump and the GOP. After all, a divided Democratic party would be a great boon to Trump's 2020 reelection bid. And clearly Trump wants to fan the flames of that divide, as we saw with his racist tweets Sunday morning, in which he wrote that he wanted AOC and her closest allies in the House -- Rep. Ilhan Omar, D-Minnesota, and Rep. Ayanna Pressley, D-Massachusetts, who are black, and Rep. Rashida Tlaib, D-Michigan, who is...