He has been relatively quiet on the issue in recent weeks, leaving all the running to other bishops.
It now looks like he is willing to spend a bit of his hard-won capital by upsetting the political establishment and commentators who wish the church would just shut up on the issue.
Long before the Coalition's controversial plan was published, Catholic teaching on the issue had been well known. For the church, any direct and deliberate act which results in the death of the unborn child is wrong and must be rejected.
Archbishop Martin – in a letter to the 'Irish Times' – has now taken issue with one aspect of the legislation in particular. He has also taken a shot at a dominant opinion that appears to invest the Supreme Court with the kind of infallibility that would make even a Pope blush.
"There is a growing impression that the judgment of the X Case 'is the Constitution'," he writes.
It is likely a thinly veiled swipe at the Taoiseach's assertion in regard to abortion law that "my book is the Constitution and the Constitution is determined by the people".
But that's the point the archbishop is disputing: the right to abortion created by the 1992 judgment was not determined by the people.
Archbishop Martin insists the X judgment is "an interpretation given in a specific case, which does not supercede or relativise the clear constitutional right to equal protection for unborn life".
His particular concern in this instance is in relation to Head 4 of the proposed legislation, which permits abortion where there is the risk of "self-destruction".
That proposal allows doctors to carry out a "medical procedure" as a "result of which unborn human life is ended" (ie an abortion).
This, Archbishop Martin insists, "would give the life of such an unborn child less protection than is guaranteed in liberal abortion laws in other countries". He doesn't elaborate.
My hunch is that he is referring to the lack of any time limit in the draft.
The explanatory note does say that "in circumstances where the unborn may be potentially viable outside the womb, doctors must make all efforts to sustain its life after delivery".
But who decides whether or not an unborn child is potentially viable outside the womb?
It
is noteworthy that Dr Martin writes "as a citizen of Ireland, who
happens also to be the Roman Catholic Archbishop of Dublin".
He is
undoubtedly trying to thwart those who would dismiss his intervention as
a throwback to an era when an opinion from Archbishop's House usually
came as a belt from a crozier.