Refuse to enable Nazi expansion, prepare for war, try to make allies. So carry on before they chose to make a pact. Making that pact with Nazis wasn't some inevitable law of nature they just had to do. You can always resist.
There's always a reason for all kinds of actions but it's just an attempt to avoid moral scrutiny to present the situation as inevitable. There were other options, they chose not to do those but rather made a pact. Agree or disagree with the decision from moral or some realpolitik sense, doesn't matter. Presenting it as inevitable is avoidance.