Senior U.S. officials were given an assessment of how the war in Ukraine is going for Kyiv’s forces, and one lawmaker called it “sobering.”

Rep. Mike Quigley (D-IL) shared his impressions after meeting in Europe with Western commanders training Ukraine’s armed forces.

“Our briefings are sobering. We’re reminded of the challenges they face,” Quigley told CNN. “This is the most difficult time of the war.”

Russia has built up several lines of defense in southern and eastern Ukraine, including vast minefields and a system of trenches that Ukrainian forces have hardly been able to penetrate. Ukraine has reportedly suffered significant losses engaging Russian defenses.

The likelihood of a Ukrainian breakthrough is reportedly low, as Ukraine’s forces are only getting more depleted, per CNN.

Asked to assess the situation from the perspective of Ukraine’s forces, retired Army Maj. Mike Lyons told CNN:

“Attacking frontal fortifications reinforced by minefields without air superiority, not a lot of times in history you can show that’s been successful. … They’re not fighting a combined arms fight, they’re not fighting a counteroffensive the way that historically’s shown has been successful. … Without the air superiority, I think this is still going to remain a stalemate.”

John Kirby, the White House National Security Council coordinator for strategic communications, acknowledged that Ukraine’s counteroffensive had disappointed, telling CNN, “Even the Ukrainians … including President Zelenskyy, have said that they’re not going as far as or as fast as he would like.”

If the counteroffensive is accepted as a failure, Ukrainian officials and their Western backers could begin blaming each other for the outcome, CNN reported.

“We did plan to start [the counteroffensive] in spring, but we didn’t,” Zelenskyy said last month at the Aspen Security Forum. “Because frankly, we have not enough munitions, and armaments, and not enough properly trained brigades. I mean properly trained in these weapons.”

A new CNN poll shows that most Americans (55%), the highest percentage since Russia invaded in February 2022, oppose authorizing more funding for Ukraine. Maj. Lyons noted that if the United States reduces its economic and military support, other Western nations might be unable to pick up the slack.

“I’m not sure that Western allies have the capability and capacity to make the difference that Ukraine is going to need in order to sustain itself. … It took us eight months to get 31 tanks to Ukraine. They need 400 if they want to have any kind of offense,” the retired major told CNN.

In an op-ed in Time, Frederick Kagan, senior fellow and director at the American Enterprise Institute, and two analysts at the Institute for the Study of War argued that Ukraine could still succeed in its counteroffensive objectives. However, the opinion piece strongly suggests that any prospect of success requires Western aircraft.

“It is baffling to hear in the West arguments that Ukraine does not need combat aircraft. NATO forces would never undertake to conduct mechanized penetrations of prepared defensive positions without air superiority. The Ukrainians are doing so now because they have no choice, but they are paying a heavy price,” reads the op-ed.