'Ukraine is fighting for the world.' Now, the world must stand and fight with it.

Martin Luther King Jr. famously wrote: “Injustice anywhere is a threat to justice everywhere. We are caught in an inescapable network of mutuality, tied in a single garment of destiny. Whatever affects one directly, affects all indirectly.”

The great American civil rights leader’s words came to mind last week when Sofiya Asher, my colleague at Indiana University and a native of Ukraine, said: “Ukraine, a country the size of Texas, is fighting for the world.”

Indeed, Ukraine, a nation of about 45 million, is fighting tooth and nail for European – and global – security. It is not a fair fight, and Ukraine needs our help.

Opinions in your inbox: Get a digest of our takes on current events every day

Ukraine is a sovereign nation whose population in 1991 voted 92% in favor of establishing a Ukrainian state independent from the Soviet Union. Russia’s devastating assault on Ukraine is just the latest sign of Vladimir Putin’s refusal to recognize Ukraine’s sovereignty, a refusal he violently signaled in 2014 by annexing Crimea and sending troops into eastern Ukraine.

He wants to reestablish the Russian empire over the bodies of dead Ukrainians.

Ukraine is in the very heart of Europe, and the cities being devastated by Russian bombs – Kyiv, Kharkiv, Odesa and others – are cities just as European as Madrid, Berlin and Milan. Would the world stand by and watch Spain, Germany or Italy be shamelessly attacked by a neighbor?

Ukrainian President Volodymyr Zelenskyy has emerged as a gritty and inspirational leader. But even Zelenskyy acknowledges that Ukraine’s future and survival largely depend on the West.

We could have, and should have, seen this coming. It is now too late to preempt the Russian military’s violent attack on Ukraine, but it is not too late to stop the war, support the Ukrainian government and the Ukrainian people, and stand on the right side of history.

Ukraine war diary: 'My 10-year-old son is now making camouflage nets for military'

Putin’s assault on Ukraine is based on outrageous lies that have nevertheless convinced many: that the people of Ukraine are fascist “radical nationalists,” that genocide has been committed against ethnic Russians in Ukraine, and that Russia now must save ethnic Russians and Russian speakers from persecution in Ukraine.

These are ridiculous untruths. Ukraine is and always has been a multiethnic, multiconfessional state whose population speaks many languages, including Ukrainian and Russian. They do not need – and never have needed – “protection” of any kind, and most certainly not by Putin.

The international community stands on the threshold of a moral abyss. Let’s be clear: The unprovoked, unjustified and murderous attack of a sovereign nation by the Russian Federation is a crime against humanity.

Ukrainians have a natural, inalienable right to self-determination and deciding their own future. Great-power politics would have us callously calculate the cost-benefit analysis of intervention, but we should just do the right thing: Give the Ukrainian people the support they need to let justice prevail.

Ukrainians' civic engagement is remarkable

With more than 25 years of doing research in Ukraine, I have seen firsthand Ukrainians’ remarkable civic consciousness, as well as the networks of care and mutual support forged by ordinary citizens to take care of one another.

Over the past three decades of economic and political upheavals, these strategies have been tested and strengthened. Ukrainians have perfected the art of caring for one another and have built a rock-solid civil society.

The Ukrainian grassroots humanitarian efforts, even while under siege, are astonishing. From bomb shelters, bunkers and subterranean subway stations, ordinary citizens are organizing emergency medical assistance, food preparation and deliveries, and all kinds of vital aid.

Nuclear attack: Russia's attack on nuclear plant was shameful. But let's not overplay the danger.

Social media apps like Facebook, Telegram and Viber create communities of concern and amplify news of what’s happening where (“street battles in Vyshneva”; “Kharkiv! Air raid warning! Everyone to shelter!") and who needs what (“Urgent! Children’s Home is running out of baby food. Here’s how you can help”).

Thanks to enduring years of Russian disinformation directed at them, Ukrainians have become very skilled at deciphering the true from the fake – yet another domain where Ukraine has been fighting for the world – and they know these messages are true, sent from trusted sources, verified and effective in doing what they are intended to do, which is help.

But as Russian battalions encircle Ukraine’s major cities, Ukrainians are running out of supplies. They are also running out of time.

My colleagues in Kharkiv, sociologists fearing for their lives in bomb shelters, tell me the city “looks like Stalingrad in World War II.” They have asked me to implore the United Nations to provide a protected evacuation corridor for citizens who wish to leave Kharkiv, Kyiv and other areas under attack. (Russia and Ukraine reportedly reached agreement Thursday to create "humanitarian corridors" to help civilians flee from combat zones. But Ukrainian officials said Sunday that Russian forces have repeatedly blocked attempts to evacuate civilians from the city of Mariupol.)

Ukrainians need food and medicine

These besieged cities desperately need convoys of humanitarian, medical and food aid. The exodus of people fleeing the war is immense. They will need food, relocation, housing, medical, psychological and employment assistance. The international community must make a sustained commitment to supporting refugees from Ukraine, now and into the long-term future.

Ukraine should not have to fight for the world. The world should stand and fight with it.

And for those who might think Ukraine does not matter, I again would invoke Martin Luther King Jr.’s observation that “whatever affects one directly, affects all indirectly.” If Ukraine falls, Putin will be even more emboldened to trample on to the next state he desires to “rebuild” in order to recreate his imagined lost empire.

Failing to boldly stand with Ukrainians now in the fight for their country would be not only a tactical error, but also a gross moral failing.

Ukrainians are defending their country and their identity, but they are also defending European democracy. Ukraine is fighting for the world, and the world must fight for Ukraine.

Sarah D. Phillips is a professor of anthropology and the director of the Robert F. Byrnes Russian and East European Institute at Indiana University.

You can read diverse opinions from our Board of Contributors and other writers on the Opinion front page, on Twitter @usatodayopinion and in our daily Opinion newsletter. To respond to a column, submit a comment to letters@usatoday.com.

This article originally appeared on USA TODAY: Ukraine is fighting Russia for the world. We must fight for Ukraine