As the U.S. continues to reckon with a widening income gap between the wealthiest Americans and marginalized communities, politicians and advocates have often cited education access as one of the greater contributors—and potential solutions—to the problem.

Improving educational opportunities to shrink income disparities depends on increasing the resources available to school districts. But funding alone is not enough to equalize access to a quality education. Schools need new and innovative approaches to turn resources into student results that beget success in the world beyond the classroom. A look back at historical challenges to education access demonstrates how far the U.S. has come, and highlights the obstacles facing students today compared with those of prior generations.

Access to education in the U.S. has improved for demographic groups across four important categories: race, class, ethnicity, and gender. But progress on these fronts has been slow and contentious. Historically, local, state, and federal leaders have instead used education as a tool to control minority populations.

Consider the forced assimilation of Native American children during the late 19th and early 20th centuries. These children were sent to boarding schools to acculturate them into a dominant white American society. They were forbidden from speaking in native tongues and were renamed for heroic historical figures like Philip Sheridan and Ulysses S. Grant. Meanwhile, Chinese and Latino children were denied equal access to education in many parts of the country as school systems, spurred on by communities’ xenophobic fears, pushed for laws or found loopholes that allowed them to segregate public schools.

These experiences extended to larger immigrant groups as well, such as the WWI-era pressure on German-American parochial schools in Texas, California, the Midwest, and major cities throughout the Northeast to forgo their ties to German culture. This discrimination grew to include forbidding non-English instruction to students of German descent, as politicians and the American public questioned whether schools founded by ethnic religious orders could be loyal to the U.S. in a time of war.

Minority ethnic groups pushed back against the restrictions as they were imposed, calling on the U.S. government to address inequalities in education access. Progress took time, accumulating in piecemeal gains for minorities.

Building on other education-related legislation throughout the 20th century, Congress took a significant step forward in 1974 with the passage of the Equal Educational Opportunities Act, which required schools to accommodate bilingual students, among other measures. In most states today, instead of shutting out non-English speaking students, K-12 schools and universities now offer programs teaching English as a second language, and hire reading and language specialists to work with students to get them past the language barrier.

In a sense, improved access to education came as a result of a more inclusive definition of citizenship in the last century. African Americans, however, have been at the center of the most contentious challenges to that inclusivity. In 1899, Cumming v. Richmond County Board of Education built upon the impact of Plessy v. Ferguson three years prior by upholding a community’s right to choose not to provide public education for black students. Parents of black children who were refused education by their local school boards were still required to pay taxes to support public education for the rest of the district, and were told to move to a district that ran a segregated school if they wanted their children to be educated.

Decades later during the civil-rights era, many Americans realized that access to education was an easy measuring stick to judge true progress for marginalized communities. That awareness wasn’t limited to U.S. citizens. Government leaders were shamed into taking action on integrating schools and rolling out new busing policies when the Soviet Union mocked segregation as evidence that the U.S. couldn’t back up its claimed principles of liberty and equality.

Today, African American enrollment at universities is steadily increasing, but there is still a 20-point gap in graduation rates between African American and white students. Despite Brown v. Board of Education, segregation is reemerging in K-12 schools, as white schools get whiter and black schools in poor, inner-city neighborhoods continue to suffer a marked achievement gap.

Scholars even point to lack of access to quality preschool programs as one indicator of later struggles. In many districts, black students in K-12 schools are also still suspended at rates disproportionate to their numbers, and college-educated blacks experienced a sharper drop in net worth and income than college-educated whites in the last decade.

It should be noted here that poor, white school districts are also cutting programs in the arts, physical education, and extracurricular activities to keep doors open, which has caused concerns about graduation rates. As with other countries, race and class are so intertwined in the U.S. that it is often difficult to distinguish whether inferior educational opportunities stem exclusively from one category or the other.

Recognizing this, the government attempted to address the impact of class on education; then-President Lyndon B. Johnson signed the Elementary and Secondary Education Act in 1965, which was designed to alleviate access to education issues for low-income students, and was reauthorized by President George W. Bush in 2002 as No Child Left Behind. Yet many Americans—teachers, parents, administrators, and politicians alike—debate whether access has improved and whether the role of class can be addressed without addressing race as well.

As schools have made progress in closing achievement gaps among racial groups, gender-related inequality has shrunk in the K-12 classroom over the last several decades. In fact, educators and scholars have even gone so far as to question whether schools have left boys behind in the effort to enhance education for girls: Most universities in the U.S. today record gender ratios that tip far toward a female majority. This is especially the case for black women, who attend college in larger numbers than black men and boast a nearly 10 percent higher graduation rate than their male counterparts.

While female students could obtain an education at several public and private universities by the mid-20th century, they still found doors closed to them professionally. Many of those doors have since opened, but even today, women experience an income gap of 21 percent. For women, improved access to education has not yet meant freedom from income inequality.

Though the country has moved past explicit policies to keep particular groups of citizens from academic opportunity, the skyrocketing costs of higher education have served as their own restriction on access—which brings us to the issue of student-loan debt.

As of 2013, nearly 70 percent of graduating college seniors had student-loan debt, averaging around $28,000 each. Many universities have struggled to keep up with shifting expectations in the last two decades, during which students have demanded increased luxuries on campus and skill-based professional programs.

Desperate for a college diploma, students sometimes resort to predatory for-profit universities (an industry now under growing scrutiny), worsening their chances of success outside of the lecture hall. Even for those students who take the traditional route through vetted universities, post-graduation incomes for many positions have remained frozen at pre-9/11 rates, leaving students to wonder if their degrees will help them in the marketplace at all.

This in turn hurts the greater economy: Anxious, cash-strapped graduates are more likely to postpone the first steps of adulthood, such as buying a car or house, or getting married. This entire crisis suggests that college has not overcome class issues to improve access to education.

Instead, Americans have come to value a college education so much, they are willing to mortgage their futures. Student debt has become a pet issue among presidential candidates, many of whom make a point of appealing to younger Americans with a sympathetic stance. It remains to be seen what impact lowering the financial barriers to higher education might have on income and academic equality.

The U.S. has made headway in educational opportunities with each generation, but improved access has thus far not served as an immediate salve for deep-seated societal problems. While resources for schools remain scarce in the current economic environment, traditionally disadvantaged populations continue to suffer the consequences.