The US is clearly starting to distance itself from project Ukraine now. That said, I don't expect that the US will alter its stance to simply admit that Russia has won. The most probable scenario is that Russia and the US will secretly negotiate a behind-the-scenes agreement, and the US will just cut aid to Ukraine while continuing to publicly engage in verbal posturing. The US admin will say that it has more pressing concerns with China and the Middle East, and it's now time for Europe to step up and assume a larger role. However, everyone knows that Europe is not any position to do so. Therefore, the conflict will likely end on Russian terms without the US openly admitting defeat. As an added bonus, the US will secure lucrative military contracts with European nations for decades to come.