The idea that the US has held back security assistance to Ukraine is nonsense. This is noted in a statement by White House press secretary Jen Psaki.

“Just last week—in the run-up to the U.S.-Russia Summit—we provided [to Ukraine] a $150 million package of security assistance, including lethal assistance.

Two days before the Summit, President Biden stood on the stage before the entire world at NATO and said that we would keep putting Ukraine ‘in the position to be able to continue to resist Russian physical aggression,’” the statement also reads.