During the president’s speech tonight, we’re likely to hear more about his plan to make community college free for all. But to really close the income gap, it’s more effective to start earlier: with four-year-olds. Several studies show that children who attend preschool are more likely go to college, keep a full-time job, and own homes as adults. Obama has called for universal pre-kindergarten in his last two State of the Unions. But given everything we know about its benefits, why isn’t universal Pre-K everywhere?