But let us be clear: No American president is going to go to war with Russia over the Ukraine. There is no compelling US national interest in a military involvement in that part of the world, and Russia is a nuclear-armed state. The steps President Biden has spoken about, including sending 8,000 US troops to countries in the vicinity of Ukraine that are allied with Washington, are (rather weak) symbolism. The threat of economic sanctions is in any case far more powerful. But Biden wouldn’t be playing such a weak hand if the US had had a unified position for the past five years and if Trump hadn’t appeared to be working for the other side.

Source: How Trump appeased Putin and Endangered Peace in Ukraine