The last time Democrats awoke to find themselves completely marginalized, the year was 2004, and George W. Bush had just been reelected , along with pretty much every other Republican in creation. Almost immediately, the party’s top donors and strategists settled on an explanation. They decided that they were losing because they lacked the campaign “infrastructure” the right commanded (think tanks, media watchdogs, voter files, etc.), and they immediately set about trying to build one. From that effort, hundreds of millions of dollars later, came groups like the Center for American Progress, which quickly became the party’s premier think tank; Media Matters, which now rules a small empire of rapid-response groups; and a company called Catalist, one of several new repositories for data on Democratic voters. (I wrote a book on all this, by the way, which seems like eons ago.) All these organizations were humming along at full capacity by the time Hillary Clinton w...