It was certainly uncouth of Rep. Joe Wilson, R-S.C., to scream out "You lie" at his commander-in-chief in the middle of Barack Obama's recent health care speech before a joint session of Congress.

And others who keep insisting that the president doesn't have an authentic U.S. birth certificate clearly come off as unhinged — much like just-resigned White House green-jobs czar Van Jones does for having signed his name to a petition stating that the Bush administration may have allowed the 9/11 murders of 3,000 people to happen.

During his speech the other night, the president calmly called for a new civility — although he had just accused his opponents of dissimulation in their attack on his health-care plan, while himself presenting many dubious suppositions as fact.

But recently the vicious rhetoric has escalated far beyond anything in the past. The smears seem reminiscent more of the brawling on the eve of the Civil War, or the nastiness during the 1960s that took decades to heal.

No one knows what the rules of engagement are now. Republicans have not forgotten that Democratic legislators loudly booed Bush during his 2005 State of the Union. Howard Dean, chairman of the Democratic Party, not long ago boasted, "I hate Republicans!"

Major politicians like former Vice President Al Gore, Sen. Robert Byrd, D-W.Va., and former Sen. John Glenn, D-Ohio, have compared George W. Bush or his supporters to Nazis or the brown shirts.

What exactly has gone wrong?

A number of things. For years, liberals were out of power. They became increasingly shrill in their frustration at George W. Bush — who seemed to set them off like no other Republican in memory.

Now that Democrats control both the Congress and the presidency, they are once more the establishment. Yet suddenly they have become angered that some conservatives, in tit-for-tat fashion, would dare resort to some of the crassness that was used to defame Bush — when any means were felt necessary to achieve the noble ends of opposing his policies.

Commentary, of course, has changed. The need for constant controversy on 24/7 cable television, nonstop blogging and ratings-driven talk radio ensure first thoughts are aired — before more sober second ones can rein in the emotion. News is entertainment. Anger sells. Slurs, not reflection, win ratings.

Another cause of the new rudeness is that the country is fragmenting. Almost every issue is dissected by its effect not on the American people as a whole, but rather on a particular constituency defined by race, class or gender. The louder and more melodramatic the accusation, the more attention and federal money follow.

Yet, just as even the gory gladiators at Rome, in their blood-soaked arena, followed a few rules, perhaps we can at least do the same:

Don't call anyone a Nazi or brown shirt. Avoid shouting down a public official. Remember that there usually aren't clear good and bad political choices, just bad and worse ones. Don't get outraged at a slur against your team, if you once made the same sort of one against the opposition.

And, most of all, remember that while we're shouting at each other, the country is at war and piling up debt at the rate of $2 trillion a year — while plenty of rivals and enemies abroad are smiling as never before.