Angry students from across the state plan to converge on Chapel Hill on Friday to protest tuition hikes the UNC system board of trustees will consider that day. The students can count the president of the United States in their corner - in principle.

President Barack Obama made a case in his State of the Union address that rising tuition is making college unaffordable for too many students - a huge problem at a time when the global economy demands a better educated U.S. workforce. Obama's remedy? He would reward colleges and universities that keep tuition low by giving them access to a $1 billion pool of grants. He would penalize those who let costs soar by cutting federal aid money.

The issue is troubling, and the president's focus is welcome. We like his plans to increase federal low-interest loan money, boost the number of work-study jobs and extend a tax credit for some college expenses. They provide help at little cost.

But we're wary of rewarding or punishing colleges based on how well they rein in costs. The plan attempts to put a one-size-fits-all shoe on the issue, leaving schools with different populations, missions, staffing needs and other criteria to wrestle with meeting an edict that's a two-headed monster: keep tuition low but quality high.

How to do that is exactly the dilemma UNC system leaders have been facing as they've tackled N.C. legislative funding cuts. The biggest cut came last year when Republican lawmakers slashed $414 million. The cuts led to crowded classes, faculty layoffs and reduced course offerings - all of which affect quality.

Such legislative cuts highlight what the president's plan does not - that public colleges and universities are at the mercy of lawmakers. Some legislators don't believe colleges should be that affordable or that the federal government should be providing aid. They'd be happy to see the schools operate on a more elite basis. This plan would provide a tool toward that goal.

The UNC system is proposing tuition and fee hikes that will average for in-state students 8.8 percent for 2012-13 (and 4.2 percent for tuition in 2013-14). Protesting students have a right to be upset. Those hikes will hamper or kill some students' ability to attend a UNC system school.

But given the legislature's deep cuts, there's little recourse. UNC system president Tom Ross said the hikes balance the demonstrated needs of the campuses with the limited ability of students and families to absorb more tuition increases. The hikes accompany a continued focus on cutting costs, bringing in more private donations and taxpayer support.

That last one, taxpayer support, is key to maintaining affordability. North Carolina has a constitutional requirement to keep the costs of attending a UNC school as low "as practicable." As a result, the state has some of the country's best schools in quality and its best in value.

Legislative cuts have jeopardized both. For that, the students and the rest of us can point at N.C. lawmakers. They unwisely gouged the system last year. They could have been more judicious by not rolling back a temporary sales tax.

They should reinstate it. State policymakers, not the federal government, have the best chance at keeping higher education costs affordable. Cutting federal funding if schools fail to keep costs down is fraught with pitfalls, and could wind up making a college education less accessible and affordable for those needing it most.