Quite the contrary. NATO and the Marshall Plan were two of the greatest successes in history. Europe would likely have gone to Stalin without them. Taft would have stood by and watched this happen. They culminated in Reagan, Thatcher, and Pope John Paul II ending the USSR.
The more recent failings of Europe and post-Soviet Russia do not change this.
I wonder what Taft’s opinion of NATO would be if he knew we were still chained to it twenty years after the Cold War. He wasn’t against the aim of blunting Soviet aggression, just the means of a treaty that could have an aggressive purpose.