That's the conclusion of a poll by YouGov.com. In the poll,
We asked one half of our survey takers the standard sort of questions about U.S. involvement in Ukraine: "Do you think the U.S. should get involved in Russia's dispute with Ukraine?" followed by some specific things that the U.S. might do (hold diplomatic negotiations with Russia, impose economic sanctions, provide economic aid, and some military options).
To the other half of the sample, we first asked "Do you think Vladimir Putin's actions in Crimea today are similar to what Hitler did in Austria and Czechoslovakia in 1938?" and "Would you consider it 'appeasement' for the U.S. and other western democracies not to take strong action to defend Ukraine?"
Results were as one might have expected:
Only 21% of those asked in the conventional way favored U.S. involvement in the Ukraine. When this question was preceded by the questions about appeasement and comparing Putin to Hitler, support for U.S. involvement rose to 29%. It didn't change the overall result -- a majority of Americans still oppose getting involved in the Ukraine even after the parallel to 1938 is mentioned -- but it does make a difference of about 8%.
Another interesting study might be an investigation of whether favoring intervention somewhere makes it more likely that one will mention Hitler in describing the situation - I'm looking at you,
Hillary.