All you need is a common enemy. Jews, a Virus, an enemy Nation, Communism, whatever. If you'll justify extreme actions to destroy that enemy, you'll justify giving the government extreme power to enact that destruction. History tells us that, once given, the government seldom lets go of such power.

Just know that in most cases where the country went to shit because of absurd levels of government power - the people saw it coming for decades, and the people gave them that power.