I served under Reagan, I can’t see his administration being so weak that he couldn’t have found effective ways to exert his power over these events, and I don’t think that he would feel so afraid that he wouldn’t even give any supplies or training, or assistance, or CIA help.
Reagan would not have created a Jimmy Carter/Obama/Rand Paul, libertarian type vacuum, for the world’s bad guys to go on the march in.
A more like response by Reagan would be to place a dozen squadrons of US Aircraft in Poland and Romania, backed by 4 armored divisions at full readiness.
Hell, that's a fitting response now.
But NOTHING in Ukraine.