Alan Keyes is a despicable lunatic. In an incredible screed now available on YouTube, Keyes denounces President Obama as a non-citizen, radical communist, abortionist, murderer bent on the destruction of the United States. He openly refuses to address President Obama by his title, instead referring to him as an “alleged usurper,” whose supposedly debatable claim to the presidency will lead to “chaos, confusion and civil war.”

Keyes again raises questions about the legitimacy of Obama’s birth certificate, even though the U.S. Supreme Court rebuffed a recent legal effort to raise this canard in court. Then he denounces Obama not only for past abortion stands, but also for his positions on immigration and mortgage relief.

What’s going on here is obvious, desperate and tragic. Republicans are so traumatized by the loss of the White House that many of them have decided to interpret the phrase “loyal opposition” to mean “complete resistance to all proposals from Democrats.” They are gambling that we will not have worked our way out of the severe economic downturn by 2010, and that a relentless, obstructionist posture will benefit them in the midterm elections.

The absence of Republican voices denouncing the irresponsible remarks is as disconcerting as Keyes’ crazy rant. Where are the voices of responsible Republican leadership disassociating the party from such poisonous accusations? The silence is telling.

There is a viciously insidious strain of racism just beneath the surface of these vile allegations about President Obama’s citizenship that bears focusing on, even if the initial impulse is to dismiss them as the ravings of a nut job. It is little surprise that Alabama Republican Sen. Richard Shelby would be among those helping to stoke such insipid rumblings, or that former Republican Party chair and Mississippi Gov. Haley Barbour would be among those suggesting that his state might not accept stimulus-package funds. Recall that over 90 percent of white voters in Alabama voted against Obama.

So what exactly are Republicans afraid of? Certainly not “chaos, confusion and civil war,” as Keyes suggests. It is doubtful that they are even truly afraid of or frustrated with Obama. What we are witnessing, through maniacal video tirades, careless remarks to reporters and other wild acts of opposition, is a party self-destructing as it struggles with its dwindling influence and creeping irrelevance as a new Democratic majority—both in Washington and nationwide—seems to take hold. They really are fearful that Obama may be the next FDR.

Obama’s inaugural address set the right tone. We have arrived at a moment when we must act responsibly. But, as he learned during the stimulus debate, sometimes you have to fight back. If Obama has a key failing thus far, it is that he has resisted tying this economic calamity squarely around the Republicans’ necks where it so rightly belongs. He will have to address head-on some of the negative onslaught coming his way. That may include openly assigning Republicans and their philosophy of “anti-government” some of the blame for the great mess we are now in.

It is tempting to dismiss the recent reappearance of Alan Keyes as a rogue rant from a man who cannot bear to stay in the shadows, where he belongs. But look and listen closely. Keyes’ arguments are filtering through his party via multiple mouthpieces. If Michael Steele is the front man, out to sell the party as Republicans say they want to be, Alan Keyes is the embarrassing reminder of the party as it still—in many ways—is. And his lunatic rhetoric is an interesting sign of just how deep Republicans’ desperation is running these days.

Lawrence Bobo is the W.E.B. Du Bois professor of the social sciences at Harvard University.