Last weekend, I led a group of 10 senators, Republicans, Democrats, and even one Independent, on a bipartisan Senate delegation visit to Poland and Germany. We traveled together to demonstrate America’s unwavering support for the freedom-loving people of Ukraine and affirm the strength of the world’s most powerful alliance. We departed with the conviction that the United States, Ukraine, and the free world have the will and the means to unite and stand up to Vladimir Putin’s tyranny.

Ukraine can win this war.

As I have mentioned before, during my time at Iowa State I had the opportunity to participate in an agricultural exchange program to Ukraine while it was still part of the Soviet Union. I saw then firsthand that the Ukrainian people hungered for freedom. That same flame still burns brightly in them today.

Today, the world is witnessing the Ukrainians’ belief in freedom through their ferocity on the battlefield and on the streets of Kharkiv, Mariupol, and Kiev. It was the same ferocity I witnessed fighting alongside Ukrainians during the Global War on Terrorism. And it’s working: Russia’s manpower and ammunition are tapping out, while, on the other side, Ukraine’s forces are hanging tough. The weapons the United States, our allies, and our partners provided are being deployed with lethal proficiency. The front lines have been frozen for over a week, and Russian casualties are greater than 1,000 a day. The Ukrainians are intercepting unclassified calls and eliminating Russian field commanders.

This past weekend, I saw firsthand the Ukrainian spirit and will to fight in eastern Poland, where we had the opportunity to hear directly from Ukrainian civil society leaders. This group of passionate, strong women delivered a clear message to the United States: we need more lethal aid–weapons, including air defense systems–and we need it as soon as possible.

They were rightly concerned by the slow pace and flow of the lethal aid Congress passed and the president has been announcing over the past few weeks. Washington bureaucracy is once again slowing the process down, and like these Ukrainian women said, there is no time to waste. Every second counts in war. We heard a similar plea from a Ukrainian refugee at a processing center near the Ukrainian-Polish border. Though humanitarian assistance is vitally important, her biggest request matched President Zelenskyy’s request to Congress a week ago: more weapons. She and others also told me that Ukraine will fight to the last man. She wants peace, but the only way she sees peace being fulfilled is if Ukraine wins the war.

The United States’ and our NATO allies’ commitment to provide lethal aid and humanitarian support to defend Ukraine from Russian tyranny is enduring. Ukraine will win this fight if we help them win this fight.

Beyond Ukraine’s borders, the trip clarified NATO’s posture against Putin’s unjust and bloody war of aggression. We are united, and it was abundantly clear that if Putin chooses to wage war against a NATO ally, he will rue the day. After discussions with U.S. commanders on the ground in Germany and Poland, I can share with confidence that the American military is primed at the tip of the spear to deter further aggression and keep Americans safe if called upon.

Pentagon Press Secretary John Kirby said recently that success for the U.S. mission in Ukraine is, at the end of this conflict, a free and independent, sovereign Ukraine. I wholeheartedly agree, but if that is our mission then we have to provide more support to enable Ukraine to win the war. America cannot hold back. I believe the U.S. should help facilitate the transfer of the Polish MiG fighter jets and follow-on by quickly backfilling Poland with our F-16s. We must also continue to flow lethal aid and weapons into Ukraine at a faster pace. Part of the solution is drawing down from pre-positioned military equipment around the world, including weapons meant for Afghan Security Forces.

Through the recent Ukraine aid package passed by Congress and signed into law, I successfully included a provision that allows the president to draw down on this pre-positioned equipment–and I will be ensuring he follows through and gets these weapons into Ukrainian hands.

Finally, it’s the consensus of America and our NATO allies that Putin must be held accountable for the crimes he has committed after Ukraine wins this war. His barbarous and cruel actions will not go unpunished. He’s bombed 400 schools, targeted maternity hospitals, and preyed on the innocent. He is a war criminal and we will hold him to account.

Going forward, America’s commitment to Ukraine and to our NATO allies must endure. Commitment to allies and partners keeps Americans prosperous, and keeps our families safe. Authoritarians, whether it’s the Taliban, Vladimir Putin, the terrorists that rule Iran, or Xi Jinping, cannot dictate terms to our security and economy. We are the world’s superpower, and we cannot be pushed around. Putin is pushing on Ukraine today, but he’s also pushing on us. Will we honor the nearly 28-year-old Budapest agreement, or surrender a key U.S. partner to a bloody lawless dictator? The choice is clear: we must stand with Ukraine. They’re ready to fight and win, and I believe they can. Mr. President, now is not the time to be risk-averse!

Authoritarianism cannot and will not prevail. Defending freedom in Ukraine is defending freedom everywhere.

U.S. Sen. Joni Ernst, a Republican, represents Iowa.