Louisiana Gov. Bobby Jindal reads from the bible during a prayer rally, Saturday, Jan. 24, 2015. (Jonathan Bachman/AP)
Opinion writer

The invasion, evidently, has begun.

“What’s not acceptable,” Louisiana Gov. Bobby Jindal (R) explained recently, “is people that want to come and conquer us.” Yes, the conquest of the United States: pretty unacceptable. “That’s not immigration, by the way,” he continued, “that’s colonization.” Ditto on being colonized, as the British learned to their chagrin. “If they want to come here and they want to set up their own culture and values, that’s not immigration, that’s really invasion ­— if you’re honest about it.”

By all means, let’s lay all the cards on the table. Jindal is talking about a Muslim fifth column, intent on establishing sharia law in unassimilated enclaves and eventually subverting the Constitution and conquering the country. A pretty serious charge against some portion of the several thousand Muslims living in Louisiana, for instance.

The proof? During a recent trip to Great Britain, Jindal was pressed for evidence of Muslim “no-go zones,” the supposed beachheads of the Islamist invasion. “I’ve heard from folks here,” he responded, “that there are neighborhoods where women don’t feel comfortable going in without veils.”

I can’t imagine that “heard from folks” would be a sufficient footnote in a paper at Oxford University (where Jindal studied as a Rhodes scholar). Yet it is apparently enough for a sitting governor making accusations of subversion. Jindal could have used his platform as a prospective presidential candidate to make points about the (very real) dangers of radicalization. Instead, he talks of invasion, colonization and conquest.

This is both appalling and symptomatic. In our politics, ideological assertions tend to gain an immediate, massive velocity. It is not enough to raise questions about global warming; it must be, according to Sen. James Inhofe (R-Okla.), the “greatest hoax ever perpetrated on the American people.” It is not sufficient to call for improved control of the border; immigrant children may be carriers of Ebola, as Rep. Phil Gingrey (R-Ga.) once asserted. It is zero to 100 in no time flat.

Some of this emerges from the feedback loop between partisan media and populist leaders (or those desperately seeking to become one). Cable and talk radio pull political ideas into close orbit, then slingshot them away at tremendous speed. Extreme language yields outrage, audience share and (hopefully) buzz in the conservative movement. Jindal leveled many of his charges on talk radio. The danger comes when talk radio becomes the voice inside your head.

The use of apocalyptic language is often a form of self-elevation. It allows a politician to embrace the role of lonely truth-seeker. “Of course,” Jindal said, “the politically correct crowd — when you say things like that, they’ll call you racist.” Only the honest and brave are willing to risk such opprobrium. Political figures who perceive the hidden threat are not only Diogenes searching for truth, they are Horatius defending the bridge against subversive Muslims, climate scientists, disease-ridden children or whatever.

This rhetorical strategy is a disaster for democratic discourse. It creates a cartoon version of reality in which actual problems are obscured or misdiagnosed. It avoids the hard work of drawing careful distinctions and offering nuanced judgments. It leaves some people on constant high alert; others are exhausted by an endless series of supposedly existential threats and unable to distinguish the real ones.

Above all, extreme rhetoric shapes a certain view of ideological opponents. Climate scientists and their allies, say some on the right, are not just mistaken, they are liars. They are acting out of corrupt financial and ideological motivations. No real debate is possible with people consciously engaged in a fraud or a hoax. They can’t be engaged; they can only be defeated. This approach becomes even more dangerous when opponents are defined in ethnic or religious terms. It creates an atmosphere in which neighbors are viewed as potential subversives.

There are, of course, comparable arguments made on the progressive side. Opponents get dismissed as theocrats or as hopeless defenders of privilege. Such people cannot be debated; they can only be delegitimized and silenced. The strategy on both left and right is the same: to present politics as a battle between the children of light and the children of darkness. Opponents become enemies. Democratic deliberation becomes difficult or impossible.

The United States has enough real problems and real enemies without the manufacture of artificial outrage.

Read more from Michael Gerson’s archive, follow him on Twitter or subscribe to his updates on Facebook .