President Volodymyr Zelenskyy has warned that if Russia manages to capture the town at the center of what's been the longest and, by most accounts, the bloodiest battle of Vladimir Putin's war on Ukraine, it could doom his country's chances of preventing Moscow from redrawing the border of democratic Eastern Europe by force. Speaking with The Associated Press, Zelenskyy said that if Bakhmut were to fall, Putin could "sell this victory to the West, to his society, to China, to Iran," as leverage to push for a ceasefire deal that would see Ukraine agree to give up territory.

"If he will feel some blood — smell that we are weak — he will push, push, push," Zelenskyy told the AP. He appeared acutely aware of the risk that his country could see its vital support from the U.S. and Europe start to slip away as the 13-month war grinds on.

"Our society will feel tired" if the Russians notch a victory, he said. "Our society will push me to have compromise with them."

Ukraine's forces, backed by increasingly lethal waves of Western weaponry and financial support, have managed to hold Russia's invading forces at bay, even clawing back some occupied ground over the last six months.

Zelenskyy knows the West's support is dependent on political leaders from Washington to Berlin continuing to accept his assertion — voiced to CBS News even before last year's invasion — that Russia's attack on Ukraine is also a direct threat to the entire democratic Western world. As the U.S. gears up for a national election that could dramatically change the level of that support, the Ukrainian leader stressed its importance.

"The United States really understands that if they stop helping us, we will not win," he told the AP.

For now, the help keeps coming. 

Heavy tanks donated by the U.K. and Germany arrived this week and are already being prepped for deployment to the front lines that stretch right across eastern Ukraine. 

While Russian forces have pushed that line to carve into Ukrainian territory near Bakhmut in the south, further north, around Ukraine's second largest city of Kharkiv, Ukraine's forces pushed the invaders back onto Russian soil after their quick advance early in the war.

Holding that line are the battle-hardened soldiers of Ukraine's 209th Battalion. Far from any halls of power, the earthen walls of trenches protect the troops as they keep a vigilant watch over the front line.

"I'll hate Russians for the rest of my life," said one soldier as he peered over the lip of the trench at the Russian positions in the distance.

Lieutenant "Lord," his call sign, has fought since the first day of Putin's full-scale invasion, when thousands of Russian forces poured across Ukraine's northern and eastern borders, including into the Kharkiv region.

Putin's new threat, issued this week, to deploy "tactical nuclear weapons" on fighter jets and ballistic missiles just across Ukraine's northern border in Belarus, now hangs over the troops east of Kharkiv.

Eyeing Russian land over the horizon, the Ukrainian soldiers were dismissive, describing Putin as an old man hurling empty threats.

"It's just blackmail," said a sergeant named Alex, "because of fewer and fewer Russian victories."

"He can deploy them on the moon," his fellow soldier Zvyaga joked about Putin's nuclear weapons. "Grandpa forgot to take his pills."

Soldiers rotate in to man the trenches for three to five days at a time. There are few human comforts on the frigid, muddy front lines.

"I try to keep my humanity," Zvyaga told CBS News. "I just want to finish and go home, have a wife, have a child."

The soldiers were optimistic that with an expected Ukrainian counteroffensive this spring, Ukraine will win the war, and their country and the line they're holding will continue to stand as a shield for democracy around the world.

In:
• War
• Nuclear Weapons
• Ukraine
• Russia
• Vladimir Putin

Ramy Inocencio

Ramy Inocencio is a foreign correspondent for CBS News based in London and previously served as Asia correspondent based in Beijing.

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