Question: How can you tell that ET is a Protestant?
Answer: Because he looks like one. As I understand it, that joke could get me and the Sunday Tribune into legal and financial trouble if we were to repeat it once Dermot Ahern's misguided new prohibition of blasphemy becomes law. The joke would have to cause "outrage" amongst a substantial number of Protestants before gardaí would be diverted from trivialities like gangland crime to arrest me, and because Protestants – no more than ET himself – don't really do outrage, I'd probably be safe enough. But what if we published some humour about Muslims, who often have a tendency to react to perceived slights like hormonal teenagers? Or Jews, many of whom see anti-Semitism in every criticism of Israel? How do you decide whether the outrage is enough to mount a prosecution, anyway? Conduct an opinion poll amongst practitioners of the insulted religion? Gauge the feeling amongst the bored and bewildered who tune into Joe Duffy's show? Count up the number of complaints to the Late Late Show after one of Tommy Tiernan's assaults on Catholicism? Ahern's law is an ass and, like all ill-conceived pieces of legislation, runs the risk of undermining the very thing – religion – it is supposed to protect. Every religious nutcase will be out of the traps making complaints to the gardaí about some perceived slight. Every comedian, satirist and polemicist worth her salt will test the new law to its limits. The only upside is that we should get to hear some very good jokes.

Comment on the proposed new law has so far focused on two questions: how will it work? Why is it being brought in now? Ahern says he wants it enacted because he is constitutionally obliged to bring in such a law.

He could, however, have proposed that the constitution be amended, to do away with the crime of blasphemy altogether, which is what was suggested by an Oireachtas committee last year. Ahern says he considers this a "costly and unwarranted diversion", which sounds plausible enough until you consider that Ireland is going to the polls next month and again in the autumn for the Lisbon referendum. If Ahern really felt that our blasphemy laws needed attention, he could have dealt with them on either of those dates.

So why now? Some, like David Quinn in the Irish Independent, have speculated that Ahern was lobbied by a religious group to bring in the new law. "It's hard to believe it was any Christian group," he wrote. "When is the last time Christians made a genuine song and dance about blasphemy, by which I mean, took to the streets in protest? Maybe it was the Muslims who lobbied them, or perhaps the government, aware that Muslims still take blasphemy very, very seriously, has decided to move to protect their sensibilities."

The reason we are getting this law now, I suspect, is less convoluted than that: Ahern is a Catholic fundamentalist in a position – for how much longer is uncertain – to introduce a law on blasphemy, and he is exploiting that advantage while he has the chance.

And it's not as if he's hiding his allegiances like some Freemason with a funny handshake. Ahern flouts his intolerance for all to see. As far back as 1993, he listened carefully in the Dáil while Fine Gael's Brendan McGahon pronounced upon the evils of homosexuality. "I regard homosexuals as being in a sad category," McGahon said, "but I believe homosexuality to be an abnormality, some type of psycho-sexual problem that has defied explanation over the years ... They endure inner torment ... Homosexuals are like lefthand drivers driving on the right side of the road."

Ahern was next to speak and made it clear that he was in full agreement with McGahon. "Will we eventually see the day when ... homosexuals will seek the right to adopt children?" he wondered.

Ahern is a serial visitor to successive popes and on one occasion at least, has assured the pontiff that Catholic policy on a particular issue would remain the policy of the Irish government. Despite EU support for the funding of human stem cell research, he told Pope Benedict in 2006 no such funding would be allowed in Ireland.

While his government drags us back to the 1980s economically, Ahern seems wedded to that decade's cultural intolerance. There is no great mystery about what is going on with this proposed new law: it's a fundamentalist charter for fundamentalist people, who will be the only ones to make use of it.