There is a constant struggle that takes place in every culture. It's a struggle between ideologies based on reason on the one hand, and ignorance on the other.
From those seeds is that most political theories germinate. And so you have the progressive approach to government and civilization, versus the regressive approach.
Progressives believe in bringing about a civilization that is secular, based on reason, and operates under the precepts of justice, equality, and the rule of law.
Regressives believe in bringing about a civilization that is based on religious fundamentalism, nationalism, racism, greed, and ethnocentrism, among other regressive attitudes.
The main challenge for a civilized society is to always be aware of the fact that there will always be a large segment of the population filled with ignorance, hate, rage and fanaticism.
As societies are able to move towards modernity under a secular government, the rage of the regressive reactionaries increases accordingly
Because their hate-filled religious books appeal to their ignorance, they come to see their struggles and claims as holy. And in their twisted sick and regressive minds they conflate race and/or cultural pride, with nationalism, and wild-eyed religious fundamentalism.
They see themselves as holy warriors. They not only see themselves as such, they tell the world they are; and they tell the world what they are going to do: Use whatever it takes, including violence, in order to achieve their goals.
They have been letting people know for many years that they are coming after progressives and liberals, in order to take down the secular government and impose their vision.
They are armed and dangerous.
The events happening in the U.S. today are contributing to these people feeling that the moment they have been waiting for has arrived: it has become a self-fulfilling prophecy.
It is very likely that the constant violent rhetoric from pundits, radio personalities, right wing extremists, religious leaders, along with acquiescence of the media (that fails to call attention to the violent rhetoric), politicians (of all parties), and the failure from the progressive movement to mount a strong (organized and disciplined) counteroffensive to the hateful ideology, will result in an increased incidence of violence.