The sound of Russian bombs, along with celebratory fireworks, will mark Ukraine's 32nd Independence Day on Thursday, Aug. 24 — 18 months into Russia's brutal and full-scale war against the sovereign nation.

Despite the war and threat from Russia, Ukrainians will celebrate the freedom they have earned with blood and unimaginable sacrifice. On Ukraine's Independence Day, the United States and its allies must recommit to the goal of helping Ukraine defeat Russia and restoring Ukraine's full sovereignty, territorial integrity and freedom.

Vladimir Putin's invasion of Ukraine poses the greatest security challenge to the international order since World War II. He bears responsibility for hundreds of thousands of deaths, the erasure of entire cities from the map, nuclear blackmail and a massive human-caused disaster not seen in Europe since Chernobyl. Ukrainians' herculean efforts at liberating their land warrant the full support of the international community, especially since nearly a fifth of the country's internationally recognized territory remains occupied by Russian forces.

Russian soldiers and collaborators routinely kill and torture Ukrainians for the crime of simply being Ukrainian, as documented by the United Nations. Russia has kidnapped more than 700,000 Ukrainian children, for which Putin has been indicted by the International Criminal Court. Some of these children were shamelessly paraded in front of Putin and bloodthirsty nationalist crowds celebrating Russia's so-called special military operation. There is a powerful case to be made under the 1948 U.N. Genocide Convention that Russia is committing genocide in Ukraine.

The American credo of "live free or die" is matched by thousands of Ukrainians, many with no previous military experience, headed to the front lines to repel the Russian invaders in the first terrifying days of this war.

Like Americans, Ukrainians are united by a common idea of liberty. And, unlike what Kremlin propaganda wants us to believe, they speak not only Ukrainian but also Russian, Hungarian and other languages freely used across the country. While certainly not his intent, Putin has encouraged Ukrainians to rally around their genuine civic and national identity in ways that transcend Ukraine's oft-exaggerated linguistic and regional cleavages.

Ukraine's declaration of independence from the Soviet Union 32 years ago was no accident; it restored historical justice. Ukraine's history is distinct and separate from Russia's and has even more conclusively diverged since 1991, as historians such as Timothy Snyder have chronicled.

Generations of Ukrainians suffered and died for the idea of an independent Ukraine, and they finally peacefully reaffirmed that dream through a popular referendum in December 1991, when more than 90% of Ukrainians — including a majority in Crimea — chose independence. And now, in his war of choice against Ukraine, Putin seeks the complete eradication of Ukraine's statehood and national identity and the subjugation of that nation into the Russian fold, much as he has tried to do with Belarus under dictator Alexander Lukashenko.

Putin has said this publicly, as has former Russian President Dmitry Medvedev in frequent and typically unhinged social media posts. Russian officials now routinely refer to democratically elected Ukrainian officials as "Nazis" and the "terrorist Kiev (sic) regime."

Ukraine's journey since hasn't been easy. In 2004, after seeing their independence threatened again by then-Prime Minister Viktor Yanukovych trying to steal the presidential election with Russian support, Ukrainians took to the streets in what became known as the Orange Revolution, leading to a do-over of the vote and the election of President Viktor Yushchenko — who was also nearly assassinated by poisoning, likely by Russian agents.

A decade later, the Ukrainians again organized mass public demonstrations after the pro-Russian Yanukovych, who by then had been elected to the presidency, backtracked on signing agreements with the European Union. The protests became known as the Revolution of Dignity, or Euromaidan. Security services loyal to Yanukovych responded with force, killing dozens of peaceful protesters. After Ukraine's parliament voted to remove him from office, Yanukovych abandoned his post and fled to Russia.

As all this was unfolding in 2014, Putin launched his initial invasion of Ukraine, including the illegal annexation of Crimea and the incursion into the Donbas region.

This history is important because Ukraine's path to liberty is similar to America's. Ukraine's survival as a free, democratic nation is also essential to our own national security, both in maintaining the post-World War II order that America helped build and the deterrence of a revanchist Beijing that may have similar designs against Taipei and escalate other conflicts with its neighbors.

Ukraine's independence continues to be tested by a rapacious Kremlin that intends to fulfill its genocidal intent. That is, unless the United States and its allies help Ukraine win. And to win, Ukraine needs more robust military and economic assistance, as well as the political will in Washington and Brussels to finally admit Ukraine as a full-fledged member of the Euro-Atlantic family, including accession to NATO and the EU. It's a privilege Ukraine has earned, tragically, in blood.

And if we fail to do our part, thousands more Ukrainians won't live to see another Independence Day.

Igor Khrestin is the Bradford M. Freeman managing director for global policy, and David J. Kramer is executive director at the George W. Bush Institute.