Rarely is anything as highly valued yet poorly managed as the creation of education policy in the United States. Year after year, and lawmaker after lawmaker, evidence has been ignored in favor of a hunch, an ideology, or the latest quick-fix scheme. If heeded, that evidence would have led lawmakers toward enhancing children’s opportunities to learn. Parents know this, of course; when we have the means we provide enriched opportunities for our children. We know that when opportunities are denied, children will learn less.

The achievement gaps that we as a nation have been (rightfully) agonizing about for many decades are nothing more than the inevitable consequence of opportunity gaps. Yet, while the nation’s education policy has been conspicuously out of balance, we can’t seem to regain our equilibrium. Doggedly, we’ve persisted with our excessive focus on measuring outcomes and demanding improvement. So, for more than two decades, even predating the No Child Left Behind law, education policy and school improvement efforts have given short shrift to capacity-building and to resources.

Policies arising out of the so-called school accountability movement have instead used student testing to identify achievement gaps and to create strong incentives to improve test scores. Regrettably, these policies have not yet led to the next step. They have not turned to well-established research evidence that explains how achievement gaps arise and how they can be closed. If we expect to make any real progress, we need to balance the measurement of outcomes with a strong attention to inputs.

The overall opportunity gap is the result of a compilation—the cumulative effect of many separate obstacles. Make no mistake: the cumulative opportunity is shocking and terrible. So while we know, for instance, that high-quality preschool is important, a child denied that opportunity will faces an even larger opportunity gap if she is also without good health and dental care, if her parents have no stable employment, and if their housing situation is unsure and transient. Her opportunity gap would grow even more if her school has inexperienced and poorly trained teachers who themselves are unlikely to remain at the school for long, if the intervention required for low test scores at her school hinges on “turnaround” approaches that result in even more churn, and if the school also faces overcrowding and has serious maintenance issues.

And the gap would continue to grow if technology and learning materials at her school are spotty and outdated, if educators and others do not understand her family’s cultural or linguistic background and assume that these are deficits that cannot be built upon, if her neighborhood is not safe and if it has few enrichment opportunities after school or over the summer. Imagine as well that she’s shunted into dead-end, low track classes that evidence what former President Bush called a “soft bigotry of low expectations.”

The list, sadly, could go on and on. Responsible policy makers cannot avoid the reality that closing the achievement gap means seriously addressing these multiple obstacles. The answers point to the need to adopt, sustain, and support the sorts of enriching best practices that we already find in many schools serving advantaged communities.

It is here, though, that we must face a troubling truth: the genuine answers are not attractive to lawmakers—particularly those lawmakers angling for votes in the next election. A magic elixir, whether bottled as test-based accountability or market-based school choice, has been the preferred policy option. From the perspective of a politician, the smart and safe path is not long-term investment. It’s short-term appeals to exciting concepts like innovation or ‘tough’ concepts like accountability. As Upton Sinclair pointed out, “It is difficult to get a man to understand something when his livelihood depends upon his not understanding it.”

Interestingly and importantly, we now have a test case in front of us. President Obama, who has in many ways failed to address opportunity gap issues, did in his February State of the Union address set forth the goal of making “high-quality preschool available to every single child in America.” He proposes a tobacco tax to fund the federal initiative. High-quality preschool has a huge long-term payoff. Support for children’s development in the first five years can set them on a more successful trajectory for a lifetime. A recent meta-analysis of the research on effects of preschool programs in the United States since 1960 finds large initial effects as well as persistent effects on a broad range of outcomes.

As President Obama said in his State of the Union address, “Study after study shows that the sooner a child begins learning, the better he or she does down the road.” His proposal amounts to a small but important step in the right direction. But as a policy proposal, it’s also the miner’s canary, the fate of which will tell us as a society whether we’re willing to make the efforts needed to close the nation’s opportunity gaps. When will we take the actions needed to heed the evidence and restore balance to our education policy?