"Too long a sacrifice / Can make a stone of the heart," the Irish poet W.B. Yeats wrote, having witnessed the violence of the 1916 Easter Rising and its aftermath.  In an America more divided than ever, and with the left more radicalized than ever, there are all too many hearts of stone.

The Washington shooting of Steve Scalise and other Republican lawmakers back in June; the attack on Sen. Rand Paul last week; and now the massacre in Southerland Springs, Texas – all of them appear to have been carried out by persons motivated at least in part by leftist ideology.  The baseball field shooter, James Hodgkinson, was a left-wing activist who hatred President Trump and targeted Republicans.  The attack on Rand Paul was reportedly carried out by a neighbor who held extremely liberal views and may have attacked Paul because of political differences.

Now there is the Texas shooter, who has been variously reported to have been a leftist and a radical atheist.  There is certainly proof that Devin Kelley posted strongly worded comments on atheism.  There is proof that he endorsed numerous liberal causes.  There is also evidence that Kelley was aligned with "United Against Fascism," a far-left political group.  Whether his political views were the primary motive for his actions remains to be seen, but clearly his attack on a conservative white church was not random.   

On Sunday, Kelley entered the First Baptist Church of Sutherland Springs, Texas and killed 26 persons between the ages of 5 and 72.  Kelley, who had received a bad conduct discharge from the Air Force in 2012 in connection with a charge of domestic violence, was linked to the Sutherland Springs church through his second wife and mother-in-law.

Violence is not the way, either on the left or the right, but it seems that the left has a particular propensity for violence.  As Edmund Burke demonstrated in his analysis of the French Revolution, the leftist ideology itself contained the seeds of violence.  The idea of revolution is fundamental to all leftist thinking, and as Robespierre asserted, in the eyes of a revolutionary, "terror is only justice: prompt, severe, and inflexible; it is therefore an emanation of virtue" (speech of Feb. 5, 1794).

In one form or another, every left-wing terrorist or tyrant since that time has ascribed to this fundamental concept – the idea that leftists' support of "justice," as they see it, confers the right to employ violence or force.  The fact that the left condones violence in the service of social justice is actually one reason for its appeal.  It is a short step from the idea that "terror is only justice" to the equally misguided idea that individuals have the right to carry out that "justice."

For the radical left, all existing structures of thought and institutions must be torn down so they can be replaced with supposedly ideal structures.  It is for this reason that the left has always employed slogans like "to the barricades"; "a New Deal"; "Occupy Wall Street"; and, simply, "forward."  "A Better Deal," the Democratic Party's current watchword, is an intentionally nondescript, ridiculous-sounding version of these revolutionary slogans, but it preserves the common idea of fundamental change.

It is this very idea that is the culprit. As long as the left adheres to Robespierre's idea that justice authorizes the use of force, there will be many willing to support revolution with violence.  Violence is part of the left's genetic code.  The entire history of leftist revolution, from Rousseau to Robespierre to Marx to Lenin and Stalin, Mao and Pol Pot, Castro and Chávez, is predicated on the idea that existing society must be transformed by means of violence – and that opponents must be liquidated unless they are willing to submit to re-education, and even if they are not.

That sort of revolutionary attitude has now become familiar to Americans as they witness the acts of groups like Antifa.  One particularly chilling aspect of these groups is the extent to which they are willing to dehumanize their opponents, whether innocent churchgoers or police officers on the beat, reducing them to nothing but inhuman stereotypes.

Even those of strongly conservative opinions do not generally fantasize about fomenting a civil war or a class war.  This is because the very nature of conservatism is rooted in the idea of "conserving" rather than destroying.

It is not in the nature of conservatives to destroy life.  Conservatives are protectors and promoters of life.  They view all life as sacred, and they are not prone to dehumanize their political opponents, no matter how strongly they disagree with them.

The true nature of conservatism, as John Paul II wrote, is to celebrate God's creation by manifesting love for one's family and fellow man.  At the same time, he warned that "social justice cannot be attained by violence.  Violence kills what it intends to create."  John Paul II recognized that every moment of life is precious because it is part of divine creation.  This is apparent to a conservative, whether he is religious in a conventional sense or not: life is filled with goodness, and our purpose is not to tear down and transform; it is to affirm and preserve.

That for me is the lesson of the recent attacks on conservatives and Christians.  I share in the grief of those who have lost family and friends, and I believe more than ever that life has purpose and goodness.  Mine is a faith – not an ideology – that could never support the executions, class wars, gulags, and assassinations perpetrated by the left.  Unfortunately, the left is not going away, and neither is its propensity for violence.  Political terrorism has not been relegated to the past – it is the present-day nature of the left, and it will continue, probably with greater force, in the future.

Recent attacks on conservatives have been appalling.  In many cases, they are intended to divide Americans and instigate further violence, leading to a leftist takeover following a period of extreme unrest.  But conservatives must not allow the mounting violence on the part of the left to draw them in.  We must remain "conservators," always protective of life, just as we are protective of life-giving institutions and traditions.  In the wake of terrible violence, we must remain conservatives in the best sense.

Jeffrey Folks is the author of many books and articles on American culture including Heartland of the Imagination (2011).