Ted Nugent, aka the Motor City Madman, an ex-rocker who's off his rocker, is at it again. Last month Nugent said:

"I have obviously failed to galvanize and prod, if not shame, enough Americans to be ever vigilant not to let a Chicago communist-raised, communist-educated, communist-nurtured subhuman mongrel like the ACORN community organizer gangster Barack Hussein Obama to weasel his way into the top office of authority in the United States."

Of that string of catchphrases, the term "subhuman mongrel" has garnered the most attention, and rightfully so.

That is the kind of wording the Nazis used to justify Jewish genocide, as Wolf Blitzer pointed out on CNN this week. In checking the statement, PolitiFact highlighted the research of David Myers, a historian at the University of California at Los Angeles, who said that the Nazis called the Jews "untermensch," or subhuman, and that that word and "mischling," or mongrel, "were intoned with daily regularity by the Nazi propaganda machine."

Furthermore, the view of blacks as subhuman chattel was a prevailing sentiment of those who tried to justify the institution of slavery in America and around the world.

And mongrel is often used as a pejorative term for a person of mixed-race heritage, which President Barack Obama is.

No matter how you cut it, Nugent was so far over the line that the line was no longer visible from where he stood.

Now, Nugent is a bit player, a bomb-thrower not worthy of much attention in his own right, but the fact that he and so many like him feel at home within the Republican Party and aligned with conservative causes is.

By no means are all, or even most, Republicans this extreme, nor do they condone this level of extremism. But far too many extremists seem to seek -- and find -- a home within the Republican ranks. There exists a foul odor of accommodation.

Nugent has been campaigning with the Texas gubernatorial candidate Greg Abbott, who demurred rather than denounce Nugent for his vile comment. The same was true of Sen. Ted Cruz of Texas, who would say only that he didn't agree with Nugent's sentiments and "You've never heard me say such a thing, nor would I."

To be sure, Democrats have sometimes gone too far as well -- by, for example, comparing the whole of the tea party to the Ku Klux Klan, as Rep. Alan Grayson did last year. And even after having his comparison rebuked by the Democratic Congressional Campaign Committee chairman, Grayson dug in his heels, refusing to apologize, instead saying "sometimes the truth hurts."

But there are two important differences here. First, the Democratic Party is not suffering a diversity crisis; the Republican Party is.

Second, the impression beginning to take hold is that the Republican Party is a home for the hateful, not necessarily because the party invites them, but because they don't forcefully enough reject them.

How does this sit with minority members in the party's ranks and those it hopes to attract? How can they be expected to find a home among such hostility? And why aren't more party leaders willing to take a stand and stamp out the bigotry?

Minority voters who happen to be conservative are looking at these incidents, no doubt, and hearing the horror of supposed friends' silence. As the Rev. Martin Luther King Jr. put it: "In the end, we will remember not the words of our enemies, but the silence of our friends."

For better or worse, ours is a two-party system, and I fervently believe that a healthy, idea-oriented opposition helps keep everyone honest. If we disagree on the size and role of government, let's have that debate. If we disagree on the role America should play in helping to police the world's quarrels, let's have that debate. If we disagree on the best way to jump start the economy, best prepare our children, fix our broken immigration system or adjust our system of taxation, let's have all those debates. But when the debate devolves into invectives born of hate -- racist, misogynistic, homophobic or otherwise -- it ceases to be healthy or productive and instead dredges up the worst of who we were and, in some cases, remain.

Nugent has since apologized, if you can call it that. He said in an interview with the conservative radio host Ben Ferguson, "I do apologize -- not necessarily to the president -- but on behalf of much better men than myself."

With people like that under the Republican tent, they may as well fold it up where minorities are concerned.

Charles M. Blow is columnist with The New York Times.