Apologies for retreading ground so clumpingly trodden last week, but a swift return to Christine O'Donnell of the Tea Party Express seems less a temptation than a moral imperative. Previously on this page, as they almost introduce the second half of US TV drama two-parters (and what a US TV drama we see unfolding here), I speculated about the remote possibility of Christine winning the Republican senatorial primary in Delaware, and what this might say about the current state of mainstream American politics.

At the time, a little was already known about the 41-year-old Palin lookalike (vaguely), endorsed by Alaska's Cretine D'Evil on her Twitter account. The unemployed Christine was known to owe some $11,000 in unpaid taxes from happier days when she wasn't, for example, at least according to the IRS; and also to have defaulted on a mortgage.

If you thought such bold defiances of candidate convention would deter fiscally hyper-conservative voters from picking her to fight the November election for Joe Biden's old Senate seat, what were you thinking? Ms O'Donnell duly whupped her centrist Republican rival, of course, and what has emerged about her since... well, it's here that the notion of thought feels like a betrayal of the senses. Sometimes, as with Harry Hill, great comedy is a visceral delight that defies intellectual analysis. This, if ever there was one, is such a time.

Fittingly enough, it fell to a fine comic to expose what for now count as Ms O'Donnell's most engaging flourishes. On HBO's Real Time, Bill Maher dug deep into the archival ground of his old show, Politically Incorrect, on which she used to appear as a pundit, and found gold in them thar clips. "I dabbled in witchcraft," she confided to him in 1999, adding that, although she never formally joined a coven, "I hung around people who were doing these things. I'm not making this stuff up... One of my first dates... We went to a movie and then had a little midnight picnic on a satanic altar."

If that were the high point of Ms O'Donnell's challenge to conventional wisdom about what American churchgoers seek in elected officials, it wouldn't be so bad. It wouldn't be so good, because the last thing anyone relying on the Christian right's votes would want is an entry in the online reference resource Wickenpedia. Even so, if Christine passed the odd witching hour with Brad or Chad, or even Damian, eating cheeseburgers and drinking Dr Pepper while getting her bobbysox splattered with blood of freshly slaughtered goat, hey, don't all college kids do crazy things? I mean, jeez, it's not like she's a Muslim, right? At least Christine didn't get herself birthed in Africa, like someone we could mention, before devilishly overcoming the limitations of colic to plant fake birth announcements in Hawaian newspapers from the crib of her Mombasa hut.

Things become a little more alarming as we reach her strictures on honesty. She may once have been a white witch (a white anything will do, you suspect, for the Tea Party), but she cannot tell a white lie. Indeed she makes George Washington look like the love child of Mr Tony Blair and Walter Mitty, and for this discovery we must thank another comedian – this time, hurrah, one of our own. As a fellow guest on Politically Incorrect, during a 1996 debate about whether it can ever be permissible to tell a falsehood, Eddie Izzard asked Christine what she'd have done if a Nazi had come to her Dutch home to enquire if she was hiding any Jews.

You may recall history's finest heckle, when a Broadway theatre-goer staggered by Pia Zadora's lead performance in The Diary of Anne Frank greeted the arrival of Nazi stormtroopers on stage by yelling "She's in the attic!" That heckler, judging by the reply she offered Izzard, might have been Christine. "I believe if I were in that situation, God would provide a way to do the right thing," she said. "You never have to practise deception. God always provides a way out." In that specific instance, presumably, via Auschwitz or Buchenwald.

Ms O'Donnell, who though regarding Aids as divine retribution is a fierce foe of masturbation, cancelled all her scheduled Sabbath day telly appearances (even one, God have mercy, on Fox News) after Maher had opened his book of revelations. And no wonder. Tea Party candidates take an admirably stern line with what Palin so drolly calls the "lamestream media". As Sharron Angle, Senate majority leader Harry Reid's opponent in Nevada, put it when bravely interviewed on Fox: "We need to have the press be our friend... We want them to ask the questions we want to answer so that they report the news the way we want it to be reported."

I want never gets, nanny used to say, and yet again, it seems the old bat was right. The oddity, or rather one among so many oddities in the captivating madhouse that is lamestream US politics, is this: those raising all the vexing questions about the lunatics hoping to take over the asylum are almost exclusively comedians. Tina Fey and Amy Poehler's devastating Palin pastiches on Saturday Night Live, Jon Stewart and Stephen Colbert on Comedy Central, Bill Maher on HBO... while the citadel of the American right is being stormed by the deranged (and to think Colin Powell thought those nice, sane neo-cons "fucking crazies"), the defence of the centre-left is in the hands of the jokers.

Even by post-Vietnam standards, this is one doozy of a culture clash. In November, when the cuckoo-bananas candidates go to the polls, we will get a better idea of whether the satirists' pens are mightier than the Tea Partiers' swords; or in Christine's case, her spells. For now, with Maher promising more clips, it's an absolute riot. But doubling up alongside the mirth is the fear that the laughter will soon fade, and that nothing but toil and trouble lie ahead.

The forces of fascism, however thick and bonkers and risible they may seem, are approaching. When they knock on electors' doors in six weeks' time, will independent voters laugh them out of town? Or will they do as Christine would have done in Holland long ago by welcoming them within?