Sen. Bernie Sanders' presidential bid has a big following on college campuses and among recent college graduates due in part to his proposal to eliminate tuition at public colleges and universities.

His plan, which was introduced as legislation last May, rests on the appealingly simple idea that a public college education should be free.

But like so many things that sound "too good to be true," free public college would come at a cost that is too high for Pennsylvania and its local economies, taxpayers, and students.

First, let's dispel the idea of "free." Free college wouldn't be free, but only a displacement of the burden from students to taxpayers. It would limit college spending to whatever the public is willing to invest; it would not change the cost of college nor what colleges actually spend to educate each student.

Tuition-free college would strain budgets and take away from important investments we could make in other areas, like pre-K programs or mental-health networks.

It would also have a profound impact on the range of higher education options.

Right now, federal aid funds follow the student, so students in Pennsylvania and elsewhere can take their aid to the institution of their choice. They can choose from a wide variety of public and private institutions, offering a myriad of educational programs, so they can select the school that best meets their needs.

In Pennsylvania, half of the baccalaureate degrees are conferred by the state's more than 100 private colleges and universities. Free public colleges would require capital and operating investments in our public colleges and universities that would likely run into the billions of dollars annually. It is hard to imagine the impact such a major policy change would have on the commonwealth's private institutions. How many of these institutions would remain viable? How many would be lost?

If those colleges were put out of business by a federal policy, it would have a devastating impact not only on students but on the dozens of small towns where local private colleges are among the most significant employers.

A better solution would be to further invest in the programs that are working.

The Pell Grant program, the bedrock of our country's investment in education, already makes college tuition free - or mostly free - for more than eight million low-income students. With a maximum award of more than $5,000, Pell Grants cover tuition at most community colleges and, when combined with need- or merit-based institutional aid, can make many public or private colleges affordable, too. It would be far better policy to double our investment in Pell Grants, broadening the number of those who can benefit from them, than to make tuition free for all, including those who have the means to pay.

Pell Grants are critical to students enrolling in schools like my own. At Susquehanna University, about a quarter of our students are Pell Grant recipients. In 2014, Susquehanna was recognized by the New York Times as one of the most economically diverse colleges in the nation. Our campus community would look far different without Pell Grants.

Ultimately, "free college" works against the long-standing tenets of the commonwealth with regard to funding for higher education. The Pennsylvania Higher Education Assistance Agency grant program provides students and their families with funds that can be used at public or private colleges in the state. It is complementary to the federal Pell Grant program and fundamental to the state's effort to make higher education accessible. A federal free-tuition policy would completely disregard our state policy, which invests significantly in students, not institutions.

As appealing as free college sounds, it is not good public policy, especially at a time when resources are strained at the local, state, and federal levels. It would disregard the philosophies of states like Pennsylvania that have remained invested in higher education. Finally, such a move would likely bring significant losses of jobs and almost certain recession to communities that are home to private colleges.

Free college really is too good to be true.

L. Jay Lemons is the president of Susquehanna University in Selinsgrove, Pa.