Former President Trump is escalating his rhetoric around immigration with less than a month to go before the Iowa caucuses — even as the Biden campaign counterattacks by arguing he is parroting Nazis. Trump in separate events over the weekend claimed migrants were “poisoning the blood of our country” and posed an increased terrorism risk, and he equated the influx of migrants at the southern border to an invasion. The “poisoning the blood” remark is not the first time Trump has used that line, which the Anti-Defamation League and others have said echoes the rhetoric of Adolf Hitler, who wrote...