Andrew argues convincingly here against Brooks's idea that the wildness of some of the Tea Party candidates is not alarming in itself, just a function of a Democratic party who would rather focus on that.
Consider this, if it is a more fundamental critique, that it is alarming in itself:
The Senate should be judged on its worst members, because it is the body which is NOT proportional representation. The integrity of the nature of the chamber is that everyone in the Senate is functioning at a higher level of representative politics. One could highlight the point even more, given how much a single Senator can influence the legislative process.
What's more, a good prosecutor can get indict a ham sandwich. If our two-party system, coupled with ennui or ressentiment, can elect a horse to be a Senator, then what does is matter if one or two may be more qualified? (This is a version of Andrew's point, but perhaps in more systematic terms.)
Last, if we worried during the Bush years about the apparent creation of an Imperial Presidency, those "lessons" appear to be translating into the Senate, at least on the GOP side, including Teapublicans. And, by that I mean candidates who do not feel they answer to anyone, really, that their broad goal is to present and stick to a "narrative", not take questions, engage in right-spirited debate, or offer to compromise. Just one of those is too many.