LOS ANGELES >> Class sizes have increased, courses have been cut and tuition has been raised — repeatedly. Fewer colleges are offering summer classes. Administrators rely increasingly on higher tuition from out-of-staters. And there are signs it could get worse: Officials say that if a tax increase proposed by Gov. Jerry Brown is not approved this year, they will be forced to consider draconian cuts like eliminating entire schools or programs.

For generations, the University of California system — home to such globally renowned institutions as Berkeley and UCLA — has been widely recognized as perhaps the best example of what public universities could be. Along with the California State University system and the state’s vast number of community colleges, higher education options here have long been the envy of other states.

But after years, and even decades, of budget cuts from the state, that reputation is under increasing threat. University leaders, who had responded typically to earlier cuts with assurances that their institutions were still in top form, are sounding the alarm. In trying to rally support, they openly worry that their schools do not offer the same quality of education as they did a decade ago.

“I’d be lying if I said what we offer students hasn’t been changed and that there hasn’t been a degradation of the learning environment,” said Timothy White, the chancellor of the University of California, Riverside, which has had record growth in recent years.

Last year, plans to open a medical school on the campus were shelved after state budget cuts.

While there are more students than ever, the number of academic advisers has dropped to 300, from 500 a few years ago, for more than 18,000 undergraduates. Courses that used to require four writing assignments now demand half that because professors have fewer assistants to help them with grading papers, something other campuses have implemented as well.

While no one is arguing that cutting higher education spending is a good thing, some say that the state budget crisis makes it necessary — and may provide an opportunity for needed changes.

Jon Coupal, the president of the Howard Jarvis Taxpayers Association, which strongly opposes the proposed tax increase, said the colleges should do more to show they are cutting spending, like reducing pay for top administrators or closing programs that do not directly benefit the state.

“We’ve had the luxury in prior years of heavily subsidizing colleges,” Coupal said. “But like anything in California, the delivery of higher education is not performance based. They’ve created new campuses and programs based on politics and not need.”

White and others say the budget concerns are beyond academic. For generations, the universities have been economic engines for the state, graduating hundreds of thousands of students each year. At every level, the universities are receiving more applicants than ever. But without more state money, colleges are struggling to find room for eligible students.

Nathan Brostrom, executive vice president of business operations for the University of California, said the system was in the middle of the worst financial crisis since the Great Depression. In the past year, the state has cut $750 million from the system’s budget. This year, for the first time, the system receives more money from tuition than from state aid — but that only makes up for roughly a quarter of the cuts from the state. Overall, the budget is the same as it was in 2007, when there were 75,000 fewer students.

In recent years, many campuses have made a more concerted effort to recruit out-of-state students, who pay more in tuition. But some have criticized the practice, and last month one state lawmaker introduced legislation to cap the number of out-of-state students.

Part of the problem, officials say, is that the amount of money provided by the state has been unpredictable, making long-term planning difficult.

“If we don’t get some kind of change this year, we are going to have an immediate unfathomable situation that really has the potential to completely change the university,” Brostrom said.

The University of California system is made up of 10 campuses, including Berkeley and UCLA, both ranked by U.S. News in the top 25 of all national universities, public or private. The California State University system, with lower tuition and easier admission requirements, is even larger, with 23 campuses and roughly 425,000 students.

Now, all but seven of the Cal State campuses are considered “impacted,” which means they have stricter admission criteria for applicants from outside the immediate area. Five years ago, only five campuses held such a distinction. Many students who attend Cal State campuses live at home to save money, which often means that if they are unable to attend a campus within driving distance they will not enroll.

The picture will grow even more dire if Brown’s tax increase does not pass in November. The president of the University of California and the chancellor of California State University are urging voters to approve the increase, saying that any more cuts would mean irreparable harm.

As it stands, community colleges will not receive the same level of financing as they did in 2007 until 2014. If voters approve the governor’s tax proposal, they stand to receive $300 million more this year, but they will lose another $300 million if the tax increase is rejected.

“We just have to get behind this initiative,” Jack Scott, the community colleges chancellor who is retiring this year, urged his colleagues in a conference call last month. “This is no time to quibble about whether the governor’s initiative is exactly what it ought to be or that you would change it here and there.”

In the most recent rounds of cuts, “campuses have tightened their belts so much that there is no more tightening to be done,” said Lawrence Pitts, academic provost for the University of California. Already, he said, the system is “certainly not providing the nature of education that we have in the past, in terms of breadth and depth, and that is something that has us terribly concerned.”

Another cut would mean contemplating things that have long been sacrosanct, like shuttering departments or eliminating an engineering school from one campus.

“Nobody wants to think about those things, but we’re beyond the point of finding efficiencies to make up for the losses,” Pitts said.

While poor students are still able to obtain financial aid, tuition increases mean that the state’s colleges may no longer be the best choice for the middle class, said Lt. Gov. Gavin Newsom, who is on the board of trustees for the UC and Cal State systems.

“This is the code red we’re in,” he said. “We’re not cutting into muscle or tissue, we’re cutting into artery.”

In one recent meeting about the Cal State budget, Newsom said, some raised the possibility of shutting down a campus, saying it could save anywhere between $44 million and $134 million, but the idea was dismissed. The system has had to cap enrollment numbers statewide to deal with the cuts.

“We’re not replacing library books, we’re not providing the kinds of student services that we need to, we’re not providing the kind of health care that we need to,” said Charles B. Reed, the chancellor of the Cal State system who recently announced his retirement. “This is supposed to be our workforce for the state. We go down this road and we’re looking at an ugly Russian winter for the economy.”

© 2012 The New York Times Company