Travel 10 miles beyond America’s capital and you would be hard pressed to find much anger about Silicon Valley. Inside Washington’s beltway, however, Big Tech’s monopoly power is rarely far from people’s minds.

In the space of a few months, the likes of Mark Zuckerberg, Facebook’s founder, and Eric Schmidt, Google’s chief executive, have gone from heroes to pariahs. The Democratic party’s new big idea is to break up the Silicon Valley groups — or to impose far tougher regulations. The problem is that most voters do not seem to share this passion. For populism to work, it should be popular.

No doubt America’s voters should be more worried about the threat of Big Tech. But liberals should beware of talking among themselves. Groupthink shields people from counter-narratives. Recall the “demography is destiny” belief that Democrats were assured of winning the White House. Or that women would vote overwhelmingly for Hillary Clinton. The idea that Russia — enabled by Facebook, Twitter and others — tipped last year’s election to Donald Trump has become an article of faith. What if voters aren’t listening? Or worse, that they think Democrats are lying?