Public schools in the United States once matched even the finest private academies in facilities and quality of instruction. But socioeconomic challenges have put public school systems under great strain and scrutiny.

The U.S. Constitution of 1787 made no mention of education, so the task of administering public schools fell to the states, and to the numerous school districts within each state. University of Michigan education professor Jeffrey Mirel notes that this meant there would never be anything like a unified "American system" of teaching children.

And he adds that today, with 93,000 public schools scattered across 50 states and their respective school districts, the U.S. education landscape is a varied one. "What we do have," he says, "are 50 different state systems and 15,000 systems within the states - quite different from Europe or Asia, where the systems tend to be highly centralized by the ministry of education in the capital city."

In early, mostly rural, America, classes met in crude schoolhouses, usually only in wintertime. The rest of the year, children worked on the family farm or their parents' shops in town.

"School," typically, was a single large room, in which older students helped teach younger ones. Their instruments were pen and ink, chalk and a blackboard, charts for mathematics and chemistry and spelling, maybe a map or two, and a literature book called a "reader." Instead of an Internet, students relied on their imaginations.

In 1837, a Massachusetts official named Horace Mann convinced his state to fund six-month public school sessions. According to New York University educational historian Diane Ravitch, "He wrote a number of reports to his state board of education, making the argument that the more you educate the children of a community, the better off the whole community will be in the long run, and that creating an educated population creates wealth for the entire community."

Universal public education caught on nationwide. And while some private - especially Catholic - schools went their own way so specific doctrines or values would be taught, public schools thrived. The nation absorbed 22 million immigrants between 1890 and 1925, and Jeffrey Mirel says the schools were the glue that held society together.

"The children of these immigrants overwhelmingly attended public schools in major cities," he points out. "And they received an education that helped them to adjust and adapt to life in the New World and the Anglo-American culture that dominates the United States in all other ways."

Big-city schools got the best teachers, paid them the most, and supplied the newest textbooks and technology. Jeff Mirel notes, though, that "in the most recent half-century, these school systems have undergone rapid and, in many ways, debilitating changes that have left them as the poster child for inefficient, unruly, and often educationally bankrupt public schools. And there is not a great deal of optimistic news. Urban public schools remain in deep trouble."

The decline began with a massive flight to the suburbs, first by whites who opposed the enforced desegregation of schools, which the U.S. Supreme Court decreed in the 1950s. Later, middle-class blacks and Hispanics also moved out of central cities in search of better schools.

Since public education is mostly paid for by taxes on property, poorer city districts had less to spend. Into their aging schoolhouses, students brought some of the surrounding community's social decay and indifference to learning.

Still, says Diane Ravitch, "There, you will find incredibly dedicated teachers, incredibly dedicated principals who are providing a safe haven for children. And they have unbelievable problems to deal with in terms of children with disabilities, children who've been abused, children who are not coming to school having had a night's sleep or a good meal."

Determined to even out the imbalance in quality between declining, mostly black, city schools, and well-equipped, mainly white suburban and rural districts, federal courts ordered that many students be bused - sometimes far away - in order to racially integrate schools.

This prompted even more so-called "white flight," and it led to the creation of new private schools exempt from government control. That left many urban schools with mostly black and Hispanic student populations all over again.

This time, says Diane Ravitch, there would be no forced busing to address the problem. "About ten years ago, the courts began saying, 'Well, you've done everything you can to desegregate your schools to eliminate any practices that would discriminate against black kids, and so you're relieved of the court order.'"

Over the years, public-school teachers and administrators were pressured to increase the social relevance of their schools. They added lessons in diversity, cultural heritage, computer technology and other so-called "touchy-feely" subjects, robbing instructional time from basic subjects.

In 1965, the federal government began paying into public education, especially to fund programs for physically and learning-disabled children. Federal money represents about ten percent of public schools' budgets, and the government is making demands on the basic curriculum. In the drive to improve reading and mathematics performance, schools now submit to an ever-increasing array of standardized tests.

Dr. Ravitch says this has provoked a backlash. "It's like saying that the only measure you'll take of your health is with a thermometer. Well, there are other measures that are important, too, and you don't become healthier by taking a thermometer and reading your temperature again and again and again."

Many parents are calling for less emphasis on testing and more attention to other basic subjects like music, history, and art.

And perhaps a little less on technology as well. Jeff Mirel at the University of Michigan says he was told that one school system in South Carolina is getting rid of textbooks, on the theory that students today are used to getting their information from computers.

"It's a ridiculous idea," he insists. "The Internet is a wonderful source of information. It's fantastic if you know what you are looking for, if you are trying to find out about a topic with which you have some basic familiarity. It is not a very good teaching system for getting people to learn the basic aspects of a particular subject."

Jeffrey Mirel and Diane Ravitch concur that a truly national system of education is unimaginable in the United States, given the power and zealous pride of local school officials and parents. But they argue that in order for children in rich and poor schools alike to succeed -- and for American students to keep up with children in nations where schools are far more regimented -- some sort of coherent, national curriculum is needed.

They and many other educators believe the country should go back to basics, all right, -- not just to math and reading drills and tests but also to curricula enriched once again through comprehensive art, music, and geography instruction, great books and lessons in citizenship.