My 4-year-old can't read yet, but she likes to pretend she can. She grabs a treasured storybook and, using pictures as a guide, repeats the lines she remembers: "Mr. McGregor said, 'Stop, thief!"'

The Tale of Peter Rabbit

is a favorite of hers.

She'll read soon enough - probably before she starts first grade - because she is growing up in a home that confers several advantages: Her mother is middle-class and college-educated; her household is full of books; and her caregivers read to her and enjoy reading for their own pleasure.

Across the country, affluent, well-educated parents know those traits boost children's achievement, which is why they spend time, money, and effort making sure that their little ones get the educational stimuli that experts insist is critical in the first few years of life. Middle-class preschoolers go to "story time," to museums, to zoos and aquariums, to well-funded preschools with small classes and skilled teachers.

Unfortunately, children from less-affluent households don't usually get the same attention, the same expensive enrichment opportunities. That's why they enter first grade behind their affluent classmates and, without educational intervention, will likely fall further and further behind.

Given that economists have long argued that better-educated workers are the key to a prosperous future, it's imperative that states start providing free high-quality preschool programs to children from poor and working-class families. So why isn't there broad political support for President Obama's plan to ramp up high-quality preschool?

The answer has nothing to do with research on the efficacy of preschool programs, or the budget deficit, or the worries of right-wingers who believe youngsters should be home-schooled. One factor limits enthusiasm for preschool education: 4-year-olds don't vote.

As a result, preschoolers from less-affluent homes don't get the educational boost they need to compete with their more fortunate counterparts.

Decades of research have proved that high-quality prekindergarten classes work. Programs, such as Head Start, which haven't stood up as well to long-term studies, are inconsistent in quality. By contrast, programs that hire well-educated teachers and put them in well-equipped classrooms with small groups of children show excellent results.

As simple as that solution is, it faces formidable political barriers, including politicians who use a newfound fiscal stinginess to argue about the costs. But when politicians complain about the money they'd have to spend for high-quality preschool classes, what they really mean is they don't want to spend so much on constituents who can't reward them at the polls. You rarely hear similar complaints about spending on elderly voters, farmers, or defense contractors.

Nor can politicians muster the political courage to spend just enough to provide high-quality pre-kindergarten education only for less-affluent families - those earning, say, less than $40,000 a year. A program that serves only the working classes and the poor would get short shrift, as Head Start has. Politicians use other, well-funded programs to pander to the middle class.

The educational achievement gap is one of the biggest reasons for growing income inequality, and one answer to that gap is an obvious one: high-quality early education. Unfortunately, our political system is at a point where it seems unable to grasp and implement simple solutions.