The Republican Party has a secret weapon for 2020. It’s especially effective because it’s stealthy: The Democrats seem oblivious to its power. And the GOP needn’t lift a finger for it to work. All Republicans have to do is sit back and watch 29-year-old Rep. Alexandria Ocasio-Cortez . . . exist.

AOC, as she’s better known, today exists largely in front of the cameras. In a few months she’s gone from an unknown New York bartender to the democratic socialist darling of the left and its media hordes. Her megaphone is so loud that she rivals Speaker Nancy Pelosi as the face of the Democratic Party. Republicans don’t know whether to applaud or laugh. Most do both.

For them, what’s not to love? She’s set off a fratricidal war on the left, with her chief of staff, Saikat Chakrabarti, this week slamming the “radical conservatives” among the Democrats holding the party “hostage.” She’s made friends with Jeremy Corbyn, leader of Britain’s Labour Party, who has been accused of anti-Semitism. She’s called the American system of wealth creation “immoral” and believes government has a duty to provide “economic security” to people who are “unwilling to work.” As a representative of New York, she’s making California look sensible.

On Thursday Ms. Ocasio-Cortez unveiled her vaunted Green New Deal, complete with the details of how Democrats plan to reach climate nirvana in a mere 10 years. It came in the form of a resolution, sponsored in the Senate by Massachusetts’ Edward Markey, on which AOC is determined to force a full House vote. That means every Democrat in Washington will get to go on the record in favor of abolishing air travel, outlawing steaks, forcing all American homeowners to retrofit their houses, putting every miner, oil rigger, livestock rancher and gas-station attendant out of a job, and spending trillions and trillions more tax money. Oh, also for government-run health care, which is somehow a prerequisite for a clean economy.

It’s a GOP dream, especially because the media presented her plan with a straight face—as a legitimate proposal from a legitimate leader in the Democratic Party. Republicans are thrilled to treat it that way in the march to 2020, as their set-piece example of what Democrats would do to the economy and average Americans if given control. The Green New Deal encapsulates everything Americans fear from government, all in one bonkers resolution.