It goes both ways: you can also destroy the foundation by being too intolerant, suspecting your friends (or they start suspecting you), leading to a Reign of Terror.

You can’t ban ideas, because they will hide behind other ideas, until you ban everything. If the AfD is banned and voters start holding blank pieces of paper and posting *** like in Russia, everyone knows what they mean, but will you start arresting people holding blank pieces of paper and posting *** like in Russia?