The Munich Agreement should not have been approved by the Parliament.
Explanation:
The Munich Agreement was at the end of a long list of policies of appeasement that ended up aggravating and resulted in the world war. This was avoidable because after the Versailles treaty either the powers could have doubled down on Germany or offered them more generous terms.
Instead what was done was that the Nazis were allowed to take over smaller territories while the allied nations sat back and watched and agreed to it. This emboldened Germany and eventually made the war possible.