For better or worse, Donald Trump is becoming a far more transformative president than many of his critics like to acknowledge. Democrats become foreign-policy hawks when the topic turns to Russia. And they morph into states’ rights activists when they want to shield illegal immigrants from deportation.

Meanwhile, conservative Never Trumpers who have spent entire careers advocating for deregulation, lower taxes, judicial restraint and colorblind public policies have abandoned those principles to make common cause with liberals and their media allies. These days, even Mr. Trump’s immediate predecessor, Barack Obama, doesn’t quite sound like his old self.

Mr. Obama traveled to Johannesburg last week to give a speech marking the 100th anniversary of Nelson Mandela’s birth, and the choicest passages sounded like gentle digs at his fellow leftists back home. Mr. Obama didn’t mention the current president by name, but he did weigh in on some current controversies, including immigration.

Democrats in Congress are under the impression that voters want our nation’s porous international borders erased rather than fixed. To that end, they are calling to abolish Immigration and Customs Enforcement, the agency that tracks down human traffickers, drug smugglers and other people who are in the country illegally.

Keep reading Jason Riley's column in the Wall Street Journal.