President Obama’s proposal to make community college tuition free got a warm hug from Gene D. Block, chancellor of the 42,000-student University of California, Los Angeles. He called it “the most encouraging idea for higher education to emerge from Washington in years.”

Block is a smart, powerful guy, a world-class biologist who runs one of the most important universities on the planet. But I am getting a more realistic appraisal from Chris Peters, a veteran teacher at El Cajon High School in Bakersfield, Calif. I have learned from years of conversations that Peters knows much more about undermotivated teenagers and community colleges than most people do.

Here is that teacher’s take on the Obama plan:

“Tuition is the least of community college students’ needs. Kids will tell you that their biggest obstacle to completing school is living expenses. They are under constant pressure to work 30-plus hours per week, and make school a second priority.”

I give Obama credit for trying to reduce tuition costs as a way to leave more dollars in a student’s pocket to pay the rent. It is simpler politically and administratively to provide financial support that way than by subsidizing food and lodging.

Unfortunately, free tuition does nothing for another big issue for Peters’ former students and just about every recent study of higher education: Community colleges provide such a disorganized mess of courses with so many dead-ends that many students never get to where they want to go.

Peters says his students complain of “overcrowding and lack of access to class. This is largely the result of community colleges (unlike four-year schools) allowing chronically unsuccessful students to keep enrolling year after year and making things harder for serious students to find classes in high reward programs such as allied health and nursing.”

In the Los Angeles Times op-ed where I found Block’s comments, the UCLA chancellor makes no mention of the scarcity of clear pathways through community colleges to four-year schools like his university, or to good jobs. Block concludes that the free tuition plan — widely supported throughout the country — “would make entering the pipeline to higher education and to four-year degrees easier for untold numbers of students in California.” The research shows pretty much the opposite.

Block appears stuck in the old mind-set that launched the community college movement. The two-year schools were invented as a low-cost way to expand college enrollment, particularly for disadvantaged students who struggled in high school. The idea has been, as Block said, that the more young people flowing into those colleges the better.

But careful analyses of community college realities reveals that the push to provide as many courses for as many students as possible has backfired. Consider this conclusion by three scholars at the Community College Research Center at Teachers College, Columbia University:

“Colleges designed to maximize course enrollment are not well designed to maximize completion of high-quality programs of study. In particular, the emphasis on low-cost enrollment has encouraged colleges to offer an array of often-disconnected courses, programs, and support services that students are expected to navigate mostly on their own.”

Peters has tried for years to educate me on what is really happening in high schools and community colleges, such as here and here. He explains that community colleges work very well for just two groups of people: high-achieving kids saving money on the first two years of college and older working adults ready for a second chance.

Regular students blunder through on their own with mostly bad results. More than 80 percent of students entering community college say they plan to graduate from a four-year school. Six years later, just 15 percent have done so.

Peters is leading a team of teachers at El Cajon High hoping to start a health careers pathway that will give many such students a better start. I’ll look at community colleges building their own trails to success, and which kind make the most sense, in my next column about community colleges.