A top Biden flak admitted that Ukraine's war with Russia is taking a toll on U.S. weapons stocks, despite the insistence of the White House that supporting Ukraine is in America's interests.

Pentagon flak John Kirby told CNN's Situation Room that the U.S. has been "drawing down on stocks quite a bit" to keep military aid flowing to the war in Europe, but he claimed that the inventories are being replenished.

Biden risking American interests?

While it may seem like Biden has been open-handed in terms of military aid, Kirby said that each shipment is carefully reviewed to ensure it won't negatively impact U.S. defense capabilities.

"We have, with every single package that the president has approved, made sure that we consult with the Pentagon and the Pentagon can reassure the entire interagency that our national security interests are not going to be compromised by the material we’re giving to Ukraine," he said.

Kirby conceded that Ukraine's war has impacted U.S. weapons inventories, however.

"Now, it is true, we’ve been drawing down on stocks quite a bit. Those inventories have got to be continually replaced. The Pentagon is prioritizing that, as you might think."

Skepticism rising

President Biden and members of both parties have argued that the Ukraine's fight for "democracy" is inextricably tied with American interests, but skepticism has grown at home.

A year into the conflict, less than half of Americans still support sending weapons to Ukraine.

A faction of "America First" Republicans have been most critical of Biden's open-ended commitment, which has cost taxpayers tens of billions of dollars.

Pentagon officials told Congress this week that they have found no indication that U.S. weapons have entered the black market in Ukraine, a country notoriously rife with corruption.

"We think the Ukrainians are using properly what they’ve been given,” the Pentagon's undersecretary of defense for policy Colin Kahl said.

Biden's open hand

Biden took a triumphant tour of Ukraine and Poland last week, where he doubled down on supporting Ukraine for "as long as it takes."

Even still, Biden has shown some sensitivity to the risks of escalation by resisting pressure from Ukraine's president Volodymyr Zelensky to supply F-16 fighter jets and long-range missiles.

Former President Trump has been a notable voice calling for negotiation to end the conflict before "World War III" erupts.