I SAID in my first post on the Tucson shooting that if the murderer turned out to be motivated by politics, there would ensue a great debate about the rancour of political discourse in America. It now transpires that Jared Loughner had no intelligible political views, but the debate has erupted anyway. So here's a plea. Let's entertain these two ideas at the same time. (1) Politicians should strive not to be so inflammatory that they incite violence. (2) Though it has its dark side, there is much to admire about political discourse in this country.

Americans take it for granted, but the first thing that strikes a visitor is that this is a country where fundamental questions are constantly aired, argued and litigated over - the size of government and the limits of its power, the meaning of equality under the law, when life begins, you name it. It is hardly surprising in this protean atmosphere that there should be a good deal of rancour. But it's unique and invigorating too. It is in fact a breath of fresh air after the soggy centralist consensus that usually prevails in Britain and much of Western Europe. The Englishman in me sometimes misses the sober and authoritative tones of the taxpayer-funded BBC. But he's also excited by the vigour of the highly partisan cable networks. Yes, much of their output is tendentious, unbalanced or downright mendacious. Yet I wonder whether they they don't occasionally conjure up some of the excitement of the polemical 18th-century pamphleteers.

What about the outright bigots, paranoids and conspiracy theorists peddling dangerous nonsense? It would be wonderful if nobody heeded their noxious messages. But, of course, it is unarguable that they must be accorded their first-amendment protections. Driving this kind of discourse underground would probably feed the paranoia and make it far more dangerous.