The Prime Minister has today reiterated that he will remain in that job until either his party dumps him or the electorate does. So Costello has been given a choice: he can challenge the Prime Minister for the leadership, or he can wait until the Prime Minister is defeated in an election and then become leader of the opposition - this hardly seems a palatable option.
Unfortunately for Costello, I suspect he has waited too long. He has been playing second fiddle so long it is difficult to imagine him as real leadership material. In addition, other MPs have been allowed time to build their own positions - most notably Malcolm Turnbull. I would expect Costello to position for a challenge early next year, lose - probably in spectacular fashion - and go off to the back bench.
The Prime Minister's position highlights the opportunistic nature of the party political principles he espouses - he has consistently said, since becoming opposition leader for the second time in 1995, that unity of the party is the most important thing. Yet the PM's stance effectively guarantees division by forcing Costello to make a challenge. Apparently unity is only of value when the party is united behind John Howard.
That is hardly a new revelation - during the periods that Peacock was leader of the Liberals, the party was effectively kept out of government by Howard's consistent and determined displays of disunity. It was only when it benefitted him, personally, that he become married to the idea that unity was of paramount importance.
This morning's statement represents one more episode of a political career motivated by personal ego and lust for power rather than a genuine interest in serving the public.