Eh, there was a decent argument for it at the time:

The launch Tuesday morning was the end of an era born in the 1990s when US government policy allowed Lockheed Martin, the original developer of the Atlas V, to use Russian rocket engines during its first stage. There was a widespread sentiment in the first decade after the fall of the Soviet Union that the United States and other Western nations should partner with Russia to keep the country’s aerospace workers employed and prevent “rogue states” like Iran or North Korea from hiring them.

ULA has enough stockpiled for the rest of the Atlas V launches, but won’t be taking delivery of any more:

Energomash exported the final batch of RD-180s to the United States in 2021, bringing the total number of deliveries to 122 engines. In the initial bulk order, each RD-180 engine was priced at approximately $10 million per unit. Energomash produced a few more RD-180s for ground testing in Russia, and those were never sent to the United States. Six RD-180 engines flew on Lockheed Martin’s Atlas III rocket, which retired in 2005, and the rest have powered Atlas Vs into space.

Aren’t their Reaver and Miranda engines Ukrainian-American, not Russian?