In the Arabic media, there are reports that Muslim clerics – energized by the sudden emergence of Egypt’s new president, Muhammad Morsi of the Muslim Brotherhood – are now agitating to demolish the Egyptian pyramids. According to agitated imams, the Pharaohs’ monuments represent “symbols of paganism” from Egypt’s pre-Islamic past and therefore must vanish.

Don’t dismiss such insanity so easily. Mali Islamists are currently destroying the centuries-old mausoleums of Sufi-Muslim saints in the city of Timbuktu, the historic site of early Islamic scholarship and jurisprudence. But perhaps the most recent regrettable Islamist attack on the past was the Taliban’s 2001 dynamiting and shelling of the huge twin 6th-century A.D. statues of Buddha carved into a cliff at Bamiyan in Afghanistan. “We are destroying the statues,” Taliban spokesmen at the time bragged, “in accordance with Islamic law, and it is purely a religious issue.”

Ideologically driven and historically ignorant violence is not just an Islamist monopoly. Sometimes postmodern, politically correct Westerners can be every bit as zealous – and as potentially destructive of the past – as premodern Islamists. One of the joys of visiting California’s Yosemite Valley is a series of historic arched bridges that span the Merced River on the valley floor. One, the 80-year-old Stoneman Bridge, is an architectural masterpiece and a tribute to Depression-era ingenuity and artistic elegance, while the sister Ahwahnee Bridge and the Sugar Pine Bridge were likewise designed to combine functionalism and beauty. All are used daily, appreciated by thousands of visitors each summer, and now are listed as endangered treasures by the National Trust for Historic Preservation.

Environmental zealots in the National Park Service are now proposing to demolish all three bridges, motivated by their pie-in-the-sky dreams of allowing the flood-prone Merced River to be freed to find its original course, without human contamination. To paraphrase the Taliban, these green fundamentalists would probably believe that the bridges are “symbols of humanism” and their destruction is “purely an environmental issue.”

Again, don’t laugh. A petition circulated by an environmental group is forcing the city of San Francisco – in a state currently struggling with a $17 billion budget shortfall – to hold a November referendum on a proposal to blow up the historic O'Shaughnessy Dam that holds back the Hetch Hetchy Reservoir. That brilliantly engineered early-20th-century water and power project still supplies San Francisco and the South Bay with as much as 85 percent of its water, while providing the city with 400 megawatts of clean electrical power, and providing Central Valley farms and towns with irrigation and flood control. Where the billions of dollars would come from to dynamite the vast dam, penstocks, pipelines and powerhouse complex and to clean up the ensuing mess, how the green electricity would be replaced, and how the Bay Area’s millions of residents would find their daily water are questions that matter little to ideologues who believe the aboriginal valley of Hetch Hetchy can be reborn without man’s baleful touch.

What do these contemporary wars against the past have in common? One shared trait is the power of ideological zealotry, whether religious or environmental, to trump all questions of practicality, historical preservation and reverence for prior generations. The zealot’s version of purity, and only his version, matters.

Modern affluence and leisure also explain both the ability and desire to destroy monuments of the past. Twenty-first-century technology allows premodern Islamists to have the weaponry, and the leisure time, for such destruction. If the statutes at Bamiyan are pagan, then so are the explosives that the Taliban used to obliterate them. And it is only because water so easily flows from San Francisco faucets, and power is a matter of flicking a switch – both impossible in 1913 when a growing San Francisco was short on clean water and newfound electricity – that today’s green imams have the latitude to dream of their own version of a pure and uncontaminated paradise.

A general historical ignorance among the public at large plays a role, too. Just as fundamentalist madrassas pound dogma into the heads of students without any historical appreciation of the richness and variety of all religions in the early Middle East, so too have politically driven courses in our own universities crowded out broad classes in history. Students in our own versions of the madrassas can recite all the commandments of their own sacred green texts, but they know very little about the nation’s past – and almost nothing about the constant poverty, physical ordeal and, yes, early death that our forefathers struggled against to ensure that we might not.

Beware of the wages of professed purity, whether religious or environmental – whether it targets a mausoleum in Timbuktu or a stone arched bridge in Yosemite.

© 2012 TRIBUNE MEDIA SERVICES, INC.