Leinster House is full of people who hate each other's guts. The laws of polite society demand that most of them manage to keep this information to themselves.
Dermot Ahern and Michael Noonan have just broken that unwritten rule -- and since both of them have a taste for strongly worded insults, their feud is set to provide plenty of entertainment.
The opening exchanges make the school playground look civilised. During a spat over the Government's spending plans on Morning Ireland, the Minister for Justice began mocking Noonan's disastrous tenure as leader of Fine Gael and noted his refusal to come off the fence during the recent heave against Enda Kenny.
The new FG finance spokesman then suddenly lashed out: "Isn't Dermot Ahern a nasty little man who keeps making personal comments about me?"
Later in the day, the "handbags at dawn" vibe became even stronger. Ahern sniggered: "Michael Noonan is becoming a bit of a caricature of himself, isn't he?" He then mocked his opponent's Limerick accent by recalling the response to a £10 increase in the old-age pension after a Celtic Tiger-era budget: "It wouldn't buy a bag of coal!"
Noonan retaliated with the grim warning that from now on the rules of Munster rugby will apply: "If somebody is consistently fouling you, you don't consistently foul them back -- you just take them out with one belt."
Maybe they should both ask themselves if they wouldn't be better off directing their fire where it might do some good. Noonan already has his hands full in trying to cope with Brian Lenihan, the most popular member of the Government, while Ahern has had to listen to home truths about his feeble response to gangland crime by new FG justice spokesman Alan Shatter.
The problem is that both men see themselves as big beasts of the political jungle, who cannot walk by a good scrap without asking somebody to hold their coat.
In his dreams, Ahern is the hard man of Fianna Fail who will be swept into the Taoiseach's office when his party finally accepts that it's being led by a loser. Noonan, at 67 he has made a remark-able comeback and now stands a fair chance of being the next Minister for Finance.
What neither of these two bruisers seems to realise is that a real tough guy knows when to shut up and keep his dignity.
Dermot Ahern and Michael Noonan both seem to be in a trigger-happy mood. The big question now is which of them will be first to shoot into his own foot.