In 1985, nearly 2,000 University of Texas students marched from the Austin campus to the Capitol steps, shouting and waving signs in protest. All because tuition was set to soar – from $4 to $12 per credit hour.

The higher price translates to $280 for a full semester in today's dollars. And today's undergraduates? They pay about $4,000 for that same semester.

When a UT committee fielded a proposal last week to raise tuition an average of 15 percent over two years, students once again complained. Another hike, another round of frustration.

The economic trends behind big increases in public college tuition reach back more than two decades. Over the last 25 years or so, many states' support for higher education has dropped as demand for expensive services such as Medicaid, prisons, and elementary and secondary education has shot up. One reason is that many states – and certainly Texas – have wanted to keep taxes low. Another is that lawmakers often consider higher education a less urgent funding priority than, say, overcrowded prisons.

Meanwhile, colleges have become increasingly competitive and expensive to run. Schools across the country compete for top students and faculty by promising up-to-date technology, fancy fitness centers, and pay packages big enough to attract good professors. This academic arms race pits public universities against their private peers, many of which have bigger endowments and more experience raising private money that give them an edge over public schools.

Through these changes, colleges have turned to students to make up the difference. In Texas, as state funding per student has dropped in absolute terms in recent years, universities have raised tuitions and fees, more than making up for the shortfall.

Nationally, at both public and private four-year colleges, tuition and fees have risen faster than inflation every year since 1980, according to the nonprofit College Board. The average charge this year is $6,185 at public universities, and $23,712 at private institutions.

As state support has dropped, many states have loosened restrictions on public colleges. That happened in Texas in 2003. Facing a gaping budget shortfall, the Legislature began allowing universities to set their own prices. Over the last four years, average tuitions in Texas have soared by more than 40 percent in inflation-adjusted dollars.

That's what prompted the latest round of opposition.

"People are taking out more and more loans," said Wesley Lewis, a junior government major at UT. Another set of tuition hikes, he said, would bring more pressure for students and their families. Already, Mr. Lewis said, the cost of college is a barrier to many people – including quite a few of his friends, who are attending more affordable community colleges in the hopes of transferring to UT later.

"The real problem is how many more people can no longer afford it," he said.

A generation ago, Texas had the least expensive public higher education in the country, thanks to heavy subsidies from state oil and gas reserves. In addition, college-going rates were relatively low.

"You could afford to have very low tuitions. And you did," said David Longanecker, executive director of the Western Interstate Commission for Higher Education, a nonprofit research organization, and a former assistant secretary at the U.S. Department of Education.

But the early 1980s brought cuts in taxes and federal programs, leaving many states scrambling to pay for education and other growing demands like prisons and health care. Then, in a particular blow to Texas, oil prices plunged. The cost of higher education didn't.

More recently, Texas has been on a mission to enroll more young people in college, especially Hispanics and students from lower-income families. That has meant hiring more faculty and staff and constructing more buildings.

It's almost ironic, Dr. Longanecker said: To send more students to college, states often have to raise tuition.

Lawmakers say they expected charges to rise after they shifted tuition-setting authority to the universities, but some express surprise that it keeps going up, especially since in the last legislative session, they boosted spending on higher education 14 percent, with the increase to take effect over the next two years. Rep. Dan Branch, R-Dallas, said he believes colleges are still catching up from prior budget shortfalls.

Calculated on a per-student basis, which accounts for growth, state support for public universities dropped from $5,872 in 2002-03 to $5,577 in 2005-06, according to the Texas Higher Education Coordinating Board. The figures are for all students, not just undergraduates, and are in inflation-adjusted dollars.

At the same time, Mr. Branch noted that other agencies also must cope with higher prices for health care and utilities. "What is it that's unique about higher ed that's causing its increase to be almost twice the normal inflation rate?" he said.

Some Democrats have outright called for re-regulation, and even some Republicans are making vague threats about the state stepping in if tuition costs don't level off soon. Many say they want more detail on why universities say they need to raise more money.

UT's tuition trends get the most attention because it is the state's biggest and most academically elite public university. Campus officials say UT uses money from tuition increases to hire more faculty, provide merit-pay raises for faculty and staff, increase financial aid for low-income students, pay for rising utility and gas prices, and fulfill other needs.

UT's proposed increases would range from 13 to 22 percent over two years for in-state undergraduates, depending on major. The 22 percent increase would apply to nursing majors – something that caught the attention of Rep. Donna Howard, D-Austin, a member of the House Higher Education Committee.

"I find that fairly ironic when we're at a point saying we need more and more people to go into nursing, and we're going to be pricing them out of attending," she said.

Colleges note that tuition deregulation has also allowed them to get more creative with their pricing. Many schools, including some University of Texas System campuses, Texas A&M University and the University of North Texas, charge flat rates whether students take 15 credit hours or 20. Some colleges give students a discount if they graduate within four years. The University of Texas at Dallas promises no tuition increases for students who finish in four years.

Any attempts to re-regulate tuition haven't gone far. House Speaker Tom Craddick, R-Midland, is an adamant supporter of deregulation. And Gov. Rick Perry has made it clear that he'll veto any bill to re-regulate tuition.

Some folks wonder, however, how serious such threats are. Why, they ask, would politicians want to put themselves back in the line of fire for making unpopular decisions to raise tuition?

The economics of higher education sometimes seem a bit odd.

At times, there's an incentive to spend money. Colleges compete for the best students, the brightest faculty and top rankings in U.S. News & World Report. Students want small class sizes, apartment-style dorms and posh recreation centers. Faculty are highly educated and expect to be paid for their expertise. Star professors who are in the most demand can bargain for smaller teaching loads, well-equipped labs and other perks.

"If you're competing for the best professors, you're going to pay more," said Mark Yudof, chancellor of the UT System. "There's an enormous competition for the brainiest people out there."

Students expect more services than they did 25 years ago, UT President William Powers said. "Students are asking for that, and they will go to a campus that has that, even if it costs a few dollars more," he said.

A good chunk of UT's tuition increase money goes toward hiring extra faculty, to keep class sizes smaller. Those cost more, obviously, than bigger classes.

Plus, U.S. News gives colleges higher marks for spending more money on students, not less.

All of those factors don't exactly give universities an incentive to spend less, Dr. Longanecker said.

On the other hand, few college students pay the sticker price. The majority receive some type of financial aid. At UT, for example, half of undergraduates receive aid – about $11,000, on average.

And colleges generally target much of their aid toward the neediest students. A growing number of public and private colleges guarantee that the poorest students – those from families making less than $40,000 a year – won't have to pay tuition or fees.

But some critics worry that current aid trends hurt middle-class families. Many colleges are adding merit scholarships to attract top students – and help their academic ranking – at the same time that they're putting more money aside for the poorest students. But few programs target middle-class families, whose incomes have remained relatively flat in real dollars in recent years.

"We can't just think about this in terms of the very poorest," said Patrick Callan, director of the National Center for Public Policy and Higher Education. "We've got to think about the middle income groups who are struggling in our society in many ways, too."

At UT, the average graduate leaves with $20,000 in debt – not much less than the average debt at private schools like Southern Methodist University and Baylor University. Schools like Texas A&M, UNT and UTD aren't far behind, with average debts ranging from $16,000 to $18,000.

Mr. Powers said UT remains affordable, even with the tuition increases, because there's also more financial aid. And, he said, it's reasonable to expect students to contribute toward their education.

"A college education helps the state, it helps the student, it helps the economy," he said. "There ought to be something more of a partnership paying [for that]."

One piece of evidence that UT hasn't priced itself out of the reach of needy students is that 21 percent of undergraduates have received federal Pell grants – available only to the lowest-income students. That's a slightly higher rate than right before tuition deregulation. At Texas A&M, it's about the same.

Many people argue, however, that like any public agency, there's always room for higher education to make more cuts and become more efficient.

Rep. Fred Brown, R-College Station, said, for example, that flagship universities, like UT and Texas A&M, leave lots of classroom space unused. Why, he and others have asked, do colleges keep adding new buildings when they don't offer more classes at night, on weekends or online?

Critics also point to high salaries for top college administrators.

In Texas, five chancellors or presidents at public colleges earned at least a half-million dollars last school year, according to a report this month from The Chronicle of Higher Education. Another six pulled in at least $400,000.

College leaders often respond that they could make far more in the private sector. And the salaries are a tiny portion of any school's total budget, for jobs that are indisputably demanding. But critics dislike the symbolism of fat paychecks when students are being asked to dig ever-deeper for tuition money.

"Do we really need to pay a public servant three quarters of a million dollars?" Dr. Longanecker said. "These are public-service jobs. We knew that when we came in."

Critics also point to huge endowments, like the UT System's, valued at more than $14 billion, and the Texas A&M System's, worth about $5.6 billion. (The endowment for UT alone is $7.2 billion.) Why not tap more into those instead of raising tuition?

College leaders respond that campuses need these nest eggs to protect against future economic downturns. Besides, donors who give to endowments often restrict how the funds can be spent. While many donors pony up for scholarships, faculty chairs and centers for specific studies, they rarely give for the kinds of general operating costs that are funded by tuition and state appropriations.

Don Stacy, a retired college professor and public school administrator, says the state should put detailed information about Texas's public colleges and how they spend money in a single, easily accessible place – similar to the Texas Education Agency's reports for elementary and secondary schools.

That would make it much easier for students, parents and taxpayers to get detailed, comparable information for all public universities in the state.

"You might find the state is providing an enormous amount of money, but the way it's spent is not the way that would be the most beneficial," said Dr. Stacy, who lives in Clifton, near Waco.

Mr. Perry has suggested funding universities based not on enrollment, but on how many students graduate. That would encourage schools to make sure students don't just start college, but finish it.

In Congress, Democrats and Republicans have united to push for more cost controls. Last week, a House committee unanimously passed a bill to control college costs, providing incentives for schools to keep price increases low. It would also create a Web site with information on college pricing, and would require colleges to report the reasons for tuition hikes, and their plans to lower costs.

Some state lawmakers say they need to keep looking for new ideas.

"The reality is that we have got to come up with another way to fund higher education in this state," said Sen. Royce West, D-Dallas, a member of the Senate Subcommittee on Higher Education.

Mr. West suggests creating local tax districts for four-year public universities, similar to those that help fund community colleges.

In the interim session, a special House committee on education finance, led by Mr. Branch, will be looking at college funding issues.

The tuitions proposed by UT and other campuses in the UT System still need approval from their governing board of regents.

"Frankly, we're going to look very hard at some of these recommendations," Mr. Yudof said.

Stephanie Gorss, a sophomore math major at UT, said she gets about $2,500 a semester in financial aid and spends about $1,600 from her own pocket. She takes a full load of classes and works 30 hours a week at a sandwich shop.

"I would not be happy at all if tuition increased," she said. "It would mean I'd have to work more and that means a lot less studying. I'm already feel like I'm working too much."

Still, Ms. Gorss said she loves going to UT. If the increases pass, she'll have to work more and take out more loans.

"I am going to be a teacher, so I'll probably be struggling to pay back these loans forever."

Staff researcher Molly Motley Blythe contributed to this report.