What should we do about the high cost of higher education? As we pick the next president, that question should feature prominently in the public debate. The economic prosperity of our children and grandchildren hinges on finding the right answer.

Today’s economy leaves little doubt about the value of college. According to the Bureau of Labor Statistics, in 2014 the median worker with a bachelor’s degree (and no advanced degree) earned $69,260, compared with $34,540 for the median worker with only a high school diploma. Over a lifetime, that difference accumulates to about $1.5 million.

Increasing educational attainment is also the best way to combat growing income inequality. Over the last 40 years, the wages of skilled workers have increased substantially compared with the wages of the unskilled. Most economists agree that a leading cause is skill-biased technological change — the tendency of new technologies to increase the relative demand for skilled workers. College is the main institution that can offset this trend by turning unskilled individuals into skilled ones.

Even those who do not attend college benefit when more of their fellow citizens do so. A person who becomes educated leaves the pool of the unskilled. Those left behind face fewer competitors. With fewer unskilled workers vying for the available jobs, wages at the bottom of the economic ladder are bid up.