“According to a national report by the State Higher Education Executive Officers Association (sheeo.org), high school graduates earn an average of almost $30,000 per year. Bachelor’s graduates earn an average of just over $50,000 a year. And those with a higher level degree (master’s, doctorate or professional) average nearly $70,000 per year. This translates to a significant earnings gap over the course of one’s life.” https://www.educationcorner.com/benefit-of-earning-a-college-degree.html “According to the SSA, the average wage in 2017 was $48,251.57.” https://wallethacks.com/average-median-income-in-america/ Moreover, college graduates generally have more interesting and secure jobs.
Who should pay for those advantages? The students themselves, or their families, have often borrowed the money to cover their educational expenses. Currently they owe $1.6 trillion “Here’s-what-trillion-student-loan-debt-is-doing-US-economy”. Democratic party presidential candidate Bernie Sanders proposes to cancel all of it. He would also make all public colleges and community colleges tuition free.
Is that a good idea? Is it fair and does it encourage or enable a better use of our human resources? A proper evaluation requires indicating who would pay for it if not the students themselves. From the above data we see that college graduates make a lot more than everyone else on average—almost double the income of high school graduates.
If the $1.6 trillion in education debt is cancelled, the burden of repaying it (most of it was lent by banks, often guaranteed by the government) will be shifted from the better off (students who will receive higher incomes in the future because of their college educations) to tax payers. Total tax collections by the federal government in 2018 were $3.3 trillion, half of which was income tax, 35% was payroll tax (social security) and only 6% was corporate income tax. https://www.pgpf.org/budget-basics/who-pays-taxes
Senator Sanders says he will cancel all student debt within six months. Does he plan to cut spending on other programs by $1.6 trillion, a 36% cut, or to increase taxes by $1.6 trillion (the deficit for FY 2019 is already forecast to be $0.9 trillion), or some mix of these? According to Charles Lane: “Sanders and other left-leaning Democrats promise to pay for tuition-free college and Medicare-for-all with higher taxes on the top 1 percent of earners. Most Nordic countries, by contrast, have zero estate tax. They fund generous programs with the help of value-added taxes that heavily affect middle-class consumers…. The Nordic countries tried direct wealth taxes such as the one that figures prominently in the plans of Sen. Elizabeth Warren (D-Mass.); all but Norway abandoned them because of widespread implementation problems.” “Democrats-use-Nordic-nations-as-models-of-socialism”
The Tax Policy Center “estimates that 69 percent of taxes collected for 2019 will come from those in the top quintile, or those earning an income above $157,900 annually. Within this group, the top one percent of income earners — those earning more than $783,300 in income per year — will contribute over a quarter of all federal revenues collected.” Can we and should we try to squeeze even more out of them?
The effective federal tax rate for the top 1% income earners in 2018 was 29.6%, compared to 12.1% for the middle quartile of income earners and 2.9% for the bottom quartile (almost none of which was income tax). It is not obvious where the burden of this gift to the prospectively better off college grads will fall. But it seems to involve a lot of income transfers, which seem to sound nice to our new “socialists.”
Warren's space 
I wish the earning potential of high school dropout workers had been included in this analysis. Surely they earn even less than those with a diploma. Secondary education is provided “free” to all students and contributes to higher lifetime incomes and tax receipts, and can be viewed, profitably or not, as a public financial investment in the student.
Using Warren’s numbers here, college graduates earn on average 2/3 more income than non-graduates, yet provide 4 times as much in federal taxes—which does not include the numerous other forms of government income—state and city income taxes, property, sales, excise, hidden, user and licensing fees, voluntary taxes like lotteries, etc. Putting aside the question of the morality of a redistributive system and who will pay for it now, the specific question for the government, assuming it is a rational actor that wishes to maximize revenue—is not whether to provide a gift, but whether an investment in college education is “profitable” to it in the long run.
The government profit perspective (net revenue, i.e., revenue minus cost) suggests targeting subsidies on the poor.