Nonetheless, it is a noble endeavour worthy of every support. Merely bringing the action, or attempting to, increases the moral and political pressure on the Iranian President.
It also should help those people within the Iranian leadership who regard Ahmadinejad as not only extreme but dangerous to Iran's own interests.
Perhaps only marginally, it will strengthen their argument that Ahmadinejad's wild and crazy and profoundly offensive rhetoric damages Iran needlessly, and therefore his nation would be better off if he were no longer president.
Of course, the Rudd Government's action also displays a profound solidarity with Israel - a solidarity that is just in itself and that will be much appreciated in Jerusalem.
It will also, incidentally, have the effect of identifying Canberra as an antagonist of Iran, which is just what it should be while Tehran's leadership is so dangerous and extreme.
However, it is extremely unlikely to succeed as a legal action and contains one small danger.
It is unlikely to succeed as a legal action simply because Iran is too powerful a state, and its oil too important to others.
Too many countries are too dependent on Iranian oil or fearful of Iranian power - both its direct military power and Tehran's long strategic reach provided through its sponsorship of numerous deadly terrorist groups. Very few countries are willing take an open stand against Iran.
Similarly, very few nations are willing to take a public stand on behalf of Israel.
Moreover, anything which requires UN Security Council approval will be vetoed by China, which protects Iran and numerous other tyrannies from any serious consequences at the UN.
The very small danger involved in taking the legal action is that it must not be seen as a substitute for the main game of denying Iran nuclear weapons, if necessary by punitive economic sanctions.
This is why the Israeli has not taken up the charge of incitement to genocide against Ahmadinejad. Israel's overwhelming priority is the physical safety of its citizens from the threat of Iranian nuclear weapons.
It does not want to invest big diplomatic and political resources into a process that will probably fail, or even if it has some partial success will probably produce only a slap on the wrist for Ahmadinejad.
Israel does not want its priorities confused.
Nonetheless, for the civilised world to tell Iran that its President's statements are indeed uncivilised is a righteous act.