This morning, at the kind invitation of House Speaker John Boehner, I attended a Joint Session of Congress to hear courageous Ukrainian President Petro Poroshenko describe Russia's threat to his country and plead for U.S. backing of his embattled nation.

It was moving to hear President Poroshenko, and heartening to see the at least superficial unanimity of Members of Congress as they stood, repeatedly, in ovations of support.

This is, I believe, the eighth time I've had the privilege of attending such Joint Sessions, including two State of the Union messages by President Clinton. At all such events, there is a general if perhaps strained sense of bonhomie among the Senators and Members of Congress as they mingle on the House floor. Among some of the Senators, particularly, there is a measure of good humor unseen during testy televised debates or hearings.

Today, for example, I noticed two of the Senators, one a respected conservative, the other a recognized liberal, laughing together as if fraternity brothers who surreptitiously had stolen their professor's tires. It was fun to see.

Three cheers for camaraderie, for friendship, for civility. But as I've written elsewhere, civility becomes a pretext for avoiding hard choices and acknowledging real and sometimes angering divisions when "being nice" supersedes the need for opposition and advocacy. Civility is the oil that prevents the gears of debate from becoming so dry with contention that they grind into civil strife. But it is not itself the purpose for which those gears are driven.

As a Christian, I believe in the depravity of man, for which reason I am grateful to awaken to streets empty of men fighting with knives and tire-irons. Civility is important in a fallen world, no question.

Courtesy and kindness are essential to any well-equipped arsenal of public discourse and action. They can sooth raw tempers and smooth rough discourse, thus making the pursuit and location of common ground possible.

Yet ultimately, civility cannot cover-over the deep chasms between worldviews and priorities existing in our society. The two Senators I noted above are both possible presidential candidates of their respective parties. They disagree on the critical issues of "faith, family, and freedom," not to mention economics and foreign policy. By virtue of the positions they have taken, Americans will have to choose not just between them as persons but between the sharply different worldviews out of which they operate and the policy conclusions resulting therefrom.

Civility can prevent verbal abuse and physical violence. To decide is to lead and often to divide, and decision-making, especially in an era when the decisions to be made represent two such fundamentally opposite set of values and arguments, is unavoidable.