It's an unwritten rule of politics and life that we generally don't blame people for their ignorance, at least when it's not their own fault. But we don't respect those who wear ignorance like a merit badge, because they're holding everyone back.

Ignorance is something that shouldn't be learned. But a willful form of it seems to be taking hold out there and it threatens to undermine a lot that is good about our liberal democracies.

This self-inflicted ignorance has produced Donald Trump as its knight in white armor and he campaigns on the ignorance platform. Trump employs knowledge denial in ways that were, until now, unseen in politics. His entire pitch is based on phony factoids.

Trump's big promise is to clamp down on criminal immigrants. Yet there are no credible statistics proving that immigrants commit more crimes than native-born Americans, as Trump claims. Nor is there a credible study proving foreigners take jobs from American workers, but he says that every day too.

Trump would abandon international trade agreements because they're all "bad deals." But while not unanimous, most economists agree that liberalized trade benefits the United States economy and its workers.

Contrary to what Trump says, the U.S. is not a hellscape of poverty and violence. Crime is decreasing and most Americans are better off now than when Barack Obama became president in 2008. Employment, even in manufacturing, is at a record high. Poverty is on the wane.

Trump's lies often have racial overtones, like his multi-year denial that Obama was born in the U.S. Now Trump claims that Hillary Clinton started the rumours. And no, the Chinese did not invent climate change to further some weird goal of theirs.

Trump's campaign is a carnival of ignorance that would have gone nowhere if more Americans had done some due diligence about his past and his character.

Instead, Trump is living proof of the inexplicable willingness of many Americans to reject factual knowledge.

His campaign arises partly from what Stanford historian Robert N. Proctor has dubbed "agnotology," defined as "culturally constructed ignorance, purposefully created by special interest groups working hard to create confusion and suppress the truth."

Agnotology works to undermine public confidence in reason and science. The best example might be the tobacco industry's use of knowledge-suppression techniques to weaken public understanding of the link between cigarette smoking and cancer.

Climate science skeptics use pseudo-factual information to blunt scientific warnings about the effects of atmospheric carbon emissions.

Culturally constructed ignorance is at the root of the anti-vaccine movement that endangers the lives of people, especially children, around the world.

And it enables politicians to claim that tax cuts for the rich, another Trump proposal, will create jobs for the working classes when they don't do any such thing.

Admittedly, not everyone is comfortable with science or data. Many people aren't sure what to think when there are uncertainties or conflicting evidence about something as complicated as climate science.

Meanwhile the skeptics get prominent media coverage of their make-believe issues, based on the poorly applied principle of journalistic balance.

That's how Trump graduated from real estate promoter to would-be statesman and presidential candidate. The media felt obliged to give his views an airing because Americans were taking them, and him, seriously.

That was enough to make Trump a factor in media coverage of the presidential campaign.

If you're inclined to deny statements that the majority know to be true, then Trump's message is appealing. By disputing facts and verifiable research, he validates society's fecklessness faction by speaking to people who, like him, can't be bothered to learn the facts.

But Trump's agnotology won't work in the real world of international politics, the economy and national security. In office, his merit badge of ignorance would tarnish pretty fast.