If you don't like Achilles, it's good to see an arrow flying straight towards his heel.
Last week in the Republic the heel belonged to Gerry Adams.
In the Irish general election campaign Sinn Fein is benefiting from an anti-austerity mood and resentment that those most responsible for wrecking the economy stayed out of jail.
At such times, those shouting loudest about unfairness and inequality get the best hearing and those who've never been in government can cast stones with impunity.
Sinn Fein is adept at trumpeting the cause of equality and human rights and denouncing golden circles, vested interests, cronyism and all the usual capitalist suspects.
But though the voters are tempted by promises of an economic and social utopia, they certainly don't want things to get worse rather than better, and definitely don't want blood on their streets.
So on Friday the 5th, the very public murder of a gangster in a crowded Dublin hotel by men dressed as gardai and armed with AK-47s frightened many.
When this was followed a few days later by a revenge shooting, with witnesses too terrified to talk to the Press, there was more alarm.
This would have been good news for Sinn Fein, except for the embarrassment caused by a line in the manifesto it had just launched.
Tucked away in the section headed 'Community Safety and Justice', it promised: "We will repeal the Offences Against The State Act."
Passed between 1939 and 1998, these laws were first designed to counter IRA terrorism and included the setting up of a non-jury Special Criminal Court (SCC) where three judges would try those considered to be a threat to State security or to the administration of justice.
In the 1990s they were extended to cover violent and ruthless criminal gangs, who like the IRA, were skilled at jury intimidation.
Adams wasn't ready for a grilling about this and put in a lamentable performance, including a denial that there was any such thing as "gangland".
It was all about civil liberties: "Everyone has the right to a jury of their peers."
Asked how juries and witnesses would be protected, he said: "You would have to go and check on those and we will, if you wish, come back in detail on that."
And then, desperately, he resorted to whingeing: "I spent four-and-a-half years imprisoned without any trial at all. Do you think that's fair?"
That didn't go down too well with people who think it even more unfair that he hasn't had life imprisonment for running the IRA.
He had to resort to hiding behind the ample skirts of Mary Lou McDonald, who explained: "Confusions arise. But I'm happy - and he is too - to set the record straight."
She unreservedly condemned the "action of gangsters and thugs" and suggested a witness protection programme, which further horrified people who just want a quiet life.
As Fianna Fáil justice spokesperson Niall Collins remarked: "Sinn Féin are a cult. They are not a political party… they want kangaroo courts but they don't want the Special Criminal Court."
Meanwhile, IRA martyr Thomas 'Slab' Murphy (Adams's "good republican" and Mary Lou's "very nice... very typical rural man of that age") was awaiting sentencing by the SCC last Friday.
The bizarre details revealed during the legal arguments that day included the allegation that poor Slab's only income is what he earns in Crossmaglen as an ill-paid yardsman on PAYE, balanced by unhelpful accounts of the hundreds of thousands of pounds seized in a raid on his farm.
Sentencing was postponed until February 26, which, oddly, is election day.
Plenty of time to remind people about the aftermath of the unsuccessful libel action Murphy took against The Sunday Times, after which Eamon Collins, who was a witness at the trial, was hideously done to death in Newry.
On Friday also it was revealed that death threats had been made to journalists at Independent News and Media, parent company of the Belfast Telegraph, causing much discussion of the murders by drug gangs of Veronica Guerin of the Sunday Independent and Martin O'Hagan of the Sunday World in Northern Ireland.
In the public mind, terrorist and criminal gangs both spell violence, the word written on the arrow aimed at Adams's heel.
Will it hit home on April 26?