[andyfox]

All politicians lie. You can tell when they're doing it: their lips are moving.

And they save their biggest whoppers for when they're going to war. Truman needed the Republicans and recalcitrant Democrats in congress to get on board for the Cold War. Thus he needed to "scare the hell" (the exact words that were used) out of the American people. The bigger and badder the enemy the bigger and badder we can be. SOP, and not just for us.

That said, it doesn't mean the Soviet Union was not a real threat. It does mean that the exaggeration of that threat and the willingness to either see or pretend to see the Soviets at the bottom of everything we didn't like led to a lot of needless suffering for a lot of people.