For several years, there has been a bi-partisan, quiet and largely undiscussed pact between Australia’s major political parties not to stir up a public debate over immigration and population. It has been an extremely rare — and extremely commendable — example of politicians putting the welfare of the country ahead of the ballot box.

Now, though, there are signals that the “sensible silence” not to exploit issues of race, immigration and population may be breaking down. In a speech today that is not coincidental in its timing, one of the Government’s most influential leaders, Lindsay Tanner, makes the case for Australia’s dynamic population growth and places that growth in the moral context of the massive populations in developing nations, especially in our own region.

It would be easy, and must be tempting, for a federal Opposition in disarray to hover their fingers over the race/immigration/population button as a way of rebuilding electoral fortunes in one simple stroke. They know, as almost everyone at the top of politics and government knows, you need only the quietest of dog whistles to incite swinging voters on this issue.

Deploying such a whistle would undoubtedly offend Malcolm Turnbull’s innate sense of decency, so let’s hope he — and especially some of his less moralistic colleagues — don’t even contemplate the choice between decency and political expediency.