The tragedy in Arizona has sparked nationwide soul-searching and calls for more civility from across the political spectrum. Seldom is there an issue on which President Barack Obama, House Speaker John Boehner, The New York Times and Sen. John McCain can agree.

At the risk of being deemed insensitive and out of touch with the times, I (respectfully) want to stress the necessity of incivility. While we all rightfully condemn the violence in Tucson, we also should recognize the value that incivility has in a democracy.

Much of the attack on incivility during the past week (and the past two years) has come from left-leaning commentators who talk as if confrontational rhetoric and disrespectful language is a right-wing monopoly. But progressives would do well to remember the honorable heritage of incivility that has helped America address serious racial, sexual and economic inequities in our past.

There is such a thing as too much civility. Surface politeness and comity can not only mask serious injustice but also discourage efforts to combat inequity. People in power often prefer civility because it means they can go unchallenged. Perhaps no one understood this better than the Rev. Martin Luther King, whose birthday we celebrated this week.

King was more than just an eloquent preacher who called us all to sit down at the table of brotherhood. He was confrontational, challenging, uncivil. His strategy of nonviolence provoked confrontation and forced uncomfortable issues of race and white supremacy to the forefront of our nation's consciousness.

King's "Letter from Birmingham Jail" is an ode to incivility. Incensed by criticism from local religious leaders that his protests were "unwise and untimely," King scribbled a strident defense of civil disobedience and nonviolent protests. The whole point of such action, King insisted, was "to create such a crisis and foster such a tension that a community which has constantly refused to negotiate is forced to confront the issue."

Civility itself was one of the significant obstacles that civil rights activists had to overcome. In "Civilities and Civil Rights," historian William Chafe dissected the ways in which the "respectable" people of Greensboro, N.C., used civility to stifle efforts by local blacks to challenge segregation and inequality. The lock that white supremacy had on Greensboro life was broken only after local students employed the decidedly uncivil act of a "sit-in" at a local Woolworth's to dramatize the injustice.

Down in Mississippi, sharecropper-turned-activist Fannie Lou Hamer was widely respected and reviled for the courageous and often uncivil ways in which she directly challenged both powerful whites and timid blacks, particularly "chicken-eating preachers" whom she accused of cowardice. She was known to march into church on a Sunday morning and loudly goad the preacher into taking a public stance in support of civil rights.

It was not just the civil rights movement that has strategically used incivility to advance democratic reforms. Being impolite, ill-mannered, and even (literally) inflammatory has often helped push our nation to live up to its founding ideals. Women's suffragist Alice Paul and her National Women's Party burned President Woodrow Wilson's portrait in effigy during a "watch fire" outside the White House. Abolitionist William Lloyd Garrison famously torched a copy of the Constitution, condemning it as a "pact with the devil." Samuel Adams and the original Tea Partiers not only turned Boston Harbor into a teapot, they also burned the tax collector in effigy.

Such incivility outraged and antagonized opponents. Civil rights activists were denounced as "outside agitators," suffragists condemned as "unpatriotic," abolitionists scorned as uncompromising "zealots" bent on destroying the Union. But ultimately, their courage inspired important social change. Not only would our history be far less colorful and interesting without the passion and incivility of Paul, Garrison, and other oft-intemperate agitators, but our country would be a much less egalitarian place.

Not all incivility, of course, is valuable, strategic or socially constructive. The hate-filled anti-authority venom that filled the streets in the late 1960s ("Off the pigs!") poisoned our politics for decades, just as some of the snarling, profanity-laced rants of anti-government extremists today only contribute to social deterioration. We absolutely should condemn violence-inciting rhetoric — freedom of speech, after all, does not exempt people from criticism for their speech.

But let's not endeavor to remove all passion and, yes, incivility from our public discourse. Doing so would diminish our democracy.

Chris Myers Asch teaches history at the University of the District of Columbia. His e-mail is casch@udc.edu.