President Donald Trump's greatest achievement within six months was simply ending illegal immigration as we had once known it--without "comprehensive immigration reform" or any other rhetorical trickery. It remains difficult to find, much less deport, the 10 to 12 million illegal aliens who entered in the last four years. Those who helped break the law, by design or indifference, now believe it was moral to destroy federal immigration law but immoral to uphold it. And it is still...