The US has already stated that it sees Crimea as Ukrainian - Russia needs to completely withdraw and be exiled. The sad thing is, there is no-one in the wings to replace Putin that would be any better unless Navalny changes his position on Ukraine as well but does appear to be Sponsored by the US
People state lots of things when wars are still 'hot'. We are not going to see a total surrender from Russia or Ukraine marching on Moscow and inflicting an absolute defeat on the Russian state. Therefore a negotiated peace is by far the most likely outcome. Russia will go in with Crimea as a red line and I suspect there will be a fudge there, such as de-militarising it.