Raise the Hammer

If the allies were so unconcerned about Moscow, then why were volunteer troops sent shortly after the formation of the Soviet government in the 1920s? This fear only deepened, especially because of the relative Russian prosperity during the depths of the Great Depression in the west, and fears that Russian agents were stirring labour unrest were rampant. The fact that Chamberlain, a conservative businessman, was an ardent anti-communist and saw Hitler as a "lesser evil" is well documented.

http://www.historyman.co.uk/road2war/

As for your history of 1939, you leave out the part months before the negotiation and signing of Stalin's treaty with Hitler where secret negotiations take place between Stalin and the French and British governments about a similar treaty. Much of the outrage expressed when the Molotov-Ribbentrop pact was based on the fact that the allies had hoped to quickly defeat Germany in a two-front war, but were unwilling to grant Russian troops entry into Poland. Molotov, himself, replaced a more western-friendly Foreign Minister (Litvinov) around this time (Stalin often made rather...bad...choices around staffing), and later had a popular Finnish drink named in his honour.

http://en.wikipedia.org/wiki/Molotov%E2%...

On the American Home Front, powerful industrialists like Henry Ford (a proud antisemite who published his views in the company newspaper) supported Hitler and fought to keep America out of the war for similar conservative reasons. There were even marches in big American cities in support. This was a very different and far more complicated conflict than our current war, and there was no easy correlation on any side between left and right and war and peace. And I think we can all agree that Chamberlain was a colossal moron for countless reasons.

As for the horrors of modern-day dictators, America has a very easy solution - it can stop funding them. Until it does, I'm going to be very sceptical about their motives. For every nasty rogue state there's a parallel among America's allies. Suharto, Pinochet, the Shah of Iran, the Saudi Monarchy, Batista, the Nicaraguan contras. Hell, the American government has funded at various times nearly all of its enemies from Ho Chi Mihn (very effective against the Japanese) and Pol Pot to the Iranian fundamentalists, Osama and Saddam. And it didn't break off the alliance with Saddam until years after he "gassed the Kurds". Beyond this, it could stop selling weapons to governments with horrible human rights records (America is the world's biggest arms dealer), and start tying some of these lucrative trade deals to things like human rights and standards of living rather than "economic policy liberalization" and support for American military goals overseas.

If the American government is sincerely trying to make the world a better place, they're some of the dumbest folks in history. If they're trying to maintain a position of global dominance, though, it all makes a sick and twisted sort of sense.