Constitutional amendments are very difficult to get up, the majority of attempts have failed. If either major political party opposes an amendment, it's essentially dead in the water. On current form the Coalition would drumbeat against it and Labor would do the bigger-badder-tougher-meanie-poo dance to try and neutralise the wedge.

Consider the fact that we are in the middle of an ongoing constitutional crisis, for which the political class knows an amendment is the only effective solution, but nobody in either major party wants to even try.