The word "nasty" was first used somewhere around 1400 CE, probably derived from the Old French word nastre which meant something bad and strange. But when used in conjunction with politics, the word 'nasty' puts me in mind of the political cartoonist Thomas Nast. Nast was the most famous cartoonist of the 19th Century, and is commonly regarded as the man who affixed to the Republican and Democratic political parties their mascot animals of elephant and donkey, respectively. Nast built his reputation and success on political attacks in his cartoons. His most common theme was to cast a well-known politician as a crook or predatory animal. That's not to say that many of Nast's targets were not the villains he cast, but Nast's cartoons were effective partly because there was no forum for debate, no available recourse for the target - if the public believed the cartoon, you were toast. While many political historians lionize Nast, it should be remembered that he introduced a new dimension to character assassination, legitimizing the caricature of people as inhuman monsters in order to persuade his audience, without any sort of debate on the facts or evidence. In many ways, the rants of Michael Moore and Keith Olbermann simply carry on the tradition of Thomas Nast, the petty venom of Peggy Noonan and George Will carry on the same behavior of an earlier flame-thrower from their party (Nast was an important player in Lincoln's 1864 re-election, and he was particularly savage in his malignment of George McLelland).
To some degree, such artists of malice are an evil we must endure; the same protection of freedom which allows one idiot to dress up as Hitler and stomp down a street on the one hand, allows David Letterman to prove himself a moronic misogynist and thug on a nightly basis on the other. But a line has been crossed when elected officials act in such manner. Without naming names, it is sadly obvious that the political world has degenerated to such a condition. We now have the closest thing to one-party rule with deliberate public disparagement of all disagreement for the first time in two generations. And as long as the public puts up with such behavior, it will remain the new standard, or become even fouler.