1. He was pushing for US energy independence, and with the pipeline and access to other production, we likely wouldn’t be in the energy pickle we are now and at the very least Ukraine would have been a Western Europe energy issue and not a U.S. issue.
2. Trump was pushing the NATO countries to absorb a greater share of defense cost and stop reliance on the US. This certainly would have advanced his objective there and he’s have stepped up with arms but extracted a high price.
I’d also add that he is unpredictable and that alone would have been a deterrent particularly since he was on defense after the false allegations about Russian collusion and intervention on his behalf in the 2016 elections.
The blame for this lies with Obama/Biden and their weak ass approach to Ukraine and Crimea.
Biden is feckless.