Today the role of America’s teachers is even bigger—they are called on to be defenders of decency and guardians of democracy because, while our democracy has never been perfect, today its very existence is threatened.

President Trump has trampled rights enshrined in the Constitution. He has waged a war on truth and scoffed at the rule of law. He has incited people to fear others for absolutely no good reason. He is enamored of despots, and distances our allies. He has put commerce and greed over human rights. He has stoked America’s divisions in order to exploit them.

Our freedoms are under attack by a president who threatens to imprison his political opponents, who openly wishes he could “get rid” of journalists, and who props up white nationalism.

Our elections are undermined by widespread voter suppression, by extreme partisan gerrymandering (which was just upheld by the Supreme Court), and by open invitations to foreign interference—with Trump even joking about it with Vladimir Putin last month.

Our very moral character as a nation is tested when government leaders portray immigrants and asylum-seekers not as people in need, but as invaders so threatening and worthless that the government’s inhumane treatment of them—denying even children adequate food, sleep and hygiene—is somehow deserved.

In a civil society, there is no “both sides” on matters of human dignity, equal rights, tolerance of diversity, truth or the rule of law. These are not options against which other beliefs can be regarded as equally worthy. But today these values need defending.

Trump is using his bully pulpit to stoke nationalism, misogyny and racism. Just recently, he hurled invectives against four congresswomen of color, suggesting they should be silenced or leave the country whose Constitution they have sworn to uphold. At a campaign rally last week, Trump whipped up an arena of mostly white supporters with his attacks on a black, female, Muslim member of Congress, amid chants of “send her back.” I have come to the chilling realization that the president of the United States, by his actions, is leading a homegrown hate movement.

Americans must be clear-eyed about the perilous time we are in. We must think seriously about what we can do to take a stand, and about the implications of doing nothing. We can’t ignore Trump’s bigotry and cruelty, or the fact that his erratic behavior is intended to create chaos and confusion. And we can’t assume things won’t get worse.

Last week I gave a speech to 1,200 educators at the American Federation of Teachers’ TEACH conference about the gravity of our situation. While this is not the first time our democracy has been at risk, today educators play a crucial role in its survival. Why? Because our members are at the nexus of public education and the labor movement, which provide direct pathways to broad-based prosperity and pluralism, and a better life.

The fight to safeguard democracy begins in America’s classrooms and schools, where we both embrace America’s diversity and forge a common identity. Our public schools are where young people develop the skills they need to be engaged and empowered citizens—voice, latitude and the ability to think for oneself. Teachers must have the freedom to teach these skills—which may not be measured on standardized tests, but which are the measure of a vibrant citizenry.

When classrooms are freed from the tyranny of standardized testing and test prep, there is time for students to analyze problems in their communities, figure out potential solutions and advocate for change. When teachers don’t have to adhere to lock-step pacing calendars, they can allow extended classroom discussions and debates. They can model democratic deliberation—where disagreements are over ideas, not people, and dissenting views are respectfully heard, not shouted down; and where opinions need to be supported with logical arguments and evidence, and not simply asserted.

Public education at its best provides a ladder of opportunity, a path out of poverty, and a place where America’s pluralism is celebrated. Democracy in education has always been the foundation for providing education for democracy.

Alexis de Tocqueville, the 19th-century observer of American democracy, wrote: “America is great because she is good. If America ceases to be good, America will cease to be great.”

When this moment in history is written, let it be said that Americans defended what is best about our country, and fought the worst. That hope won against fear, aspiration over frustration, and humanity over cruelty. That we defeated demagoguery. And that our public schools were a sturdy cornerstone helping to preserve our democracy.