To be clear, USAF awarded ULA (United Launch Alliance, jointly run by Boeing and Lockheed) the uncompeted contract. What this prevents is ULA from making purchases from Russia for parts, which essentially cripples their entire contract since the Russian parts included the first-stage engine I believe. Without that, ULA doesn't have a functional rocket as far as I can tell. I'm sure ULA will find an intermediary who will "just happen" to have some of these engines laying around that they can then use to fulfill the contract. The bigger question is whether the contract as a whole will be recompeted, as it should.