What explains the inability of money to decisively shape public opinion? For one thing, social media has empowered candidates to communicate with voters, both directly and by way of the more traditional media, which eagerly follows an online buzz once it starts and grows to a critical mass. Just ask Donald Trump — a candidate who had more of his own money to spend than anyone else and who, thanks to a six-month barrage of tweets and outrageous comments to media outlets, managed to buy himself the equivalent of a billion-dollar’s worth of free advertising.

But that isn’t a sufficient explanation. For that we need to remember the old adage immortalized by the Beatles: Money (and attention) can’t buy you love. Trump might have tweeted up a storm and been ignored, or been treated by likely voters as the sideshow that so many commentators originally took his campaign to be. Instead, they liked what they heard from him and rallied to his side.

All the money and tweets in the world won’t matter if the people don’t like the message and the messenger. (I’m looking at you, Jeb and Marco.)

This is a crucially important point for progressives — because they need to get this right. The case for regulating and limiting money in politics needs to be based on facts. It might seem wrong in some abstract sense for a small group of people or families to be permitted to spend their fortunes on funding their preferred presidential contenders. But if that money is largely ineffective, reform efforts should be directed elsewhere.