There are many different short-and long-term perspectives on the surprise appointment of former NSW premier Bob Carr as the Minister for Foreign Affairs to replace Kevin Rudd. Most of these perspectives have been already canvassed. But it is a useful exercise to put them all together, because on weighing up the pros and the cons there is no clear answer to the question of whether it is a good move or not. Only time and Carr's performance will tell.

There has always been constant speculation about the move of heavy hitters from state parliaments to the federal sphere to rescue or bolster the fortunes of their party. Some MPs make the move from former premier or chief minister or opposition leader. A much larger number move from more junior positions in state Parliaments. Most moves occur through standing for a House of Representatives or Senate seat in the usual way, but some enter as Senate replacements.

So Carr's move to federal politics was not unusual in itself. What was unusual was the speed with which it all happened after Mark Arbib's surprise resignation, and his immediate elevation into a senior portfolio. It was all within the parliamentary rules and conventions but, despite earlier general speculation about some former state Labor premiers moving into the federal government, totally unpredicted.

Carr has personal qualities and experience. If he had chosen to enter federal parliament in 2007 or 2010 in the usual way, after retiring as premier in 2005, he would have ended up in a senior portfolio in the Rudd and Gillard governments just as John Fahey did in the Howard government. Fahey, NSW premier before Carr defeated him, entered federal parliament in 1996,and immediately became John Howard's minister for finance.

Opinions of Carr's 10 years as NSW premier vary widely. But he is experienced in Parliament and in the community, has a demonstrated interest in foreign affairs, and brings personal stature and style. Since his appointment there have been many supportive testimonials from the foreign affairs community. One benefit for the Gillard government might be the admiration for Carr expressed by prominent conservative commentators, such as Greg Sheridan.

Carr might even be better for the break from politics. Many long-serving politicians would be better for some time out, though Howard seemed not to need it over more than 30 years. It is rarely possible in the Australian system yet, given his commercial and intellectual interlude, Carr might turn out to be better second time around in his first love.

Another big benefit for the government of Carr's appointment is that it undoubtedly wrong footed the opposition. One of the golden rules of good politics is to be unpredictable. Gillard certainly has done that.

Carr is also an impeccable foil for Rudd. He counterbalances admirably Rudd's potential foreign policy grievances from the backbench. While the opposition might claim that it reflects poorly on Labor's parliamentary talent, that is a hollow criticism as parties are always trying to bolster their talent pool.

On the Coalition side former senior Howard adviser Arthur Sinodinos, though lacking parliamentary experience, is a case in point. While Tony Abbott has not rushed him into the shadow ministry, Sinodinos will certainly have a senior portfolio in any future Abbott government.

Nevertheless Carr's queue-jumping appointment was always sure to ruffle the feathers of other possible appointees. Stephen Smith had already taken one for the side in 2010 when he made way for Rudd. A parallel in the bureaucratic world is the disappointment felt by serving diplomats when a former politician, like Kim Beazley or Andrew Peacock, is parachuted into a plumb diplomatic position like ambassador to Washington.

The Carr case has also raised the fascinating question of whether Senate vacancies might become a way of expanding the restricted ministerial talent pool in parliamentary systems when compared to presidential systems. Bob Hawke pondered the question of outside appointments to cabinet in his 1979 Boyer Lecture.

There are enough unelected Senate replacements on both sides to make it a real avenue for bringing high-profile people into cabinet for just a short stint to fill a gap.

But if it was overdone there would be a deservedly adverse reaction against the practice as a manipulation of the system. Parliamentarians are meant to be elected and Senate replacements are a loophole.

It would be far better for a political party to find a safe seat in the House of Representatives before putting that person in cabinet, despite necessarily telegraphing your punches to your opponents as it can't be done as quickly.

On the negative side the appointment is also a case of missed opportunities, both related to the speed of the replacement. The idea seems to have come initially from NSW state secretary, Sam Dastyari, on the same day as Arbib's announcement of his retirement.

While other names were canvassed their suitability was quickly dismissed. Is that the way a democratic party should operate?

Labor would have benefited in community esteem from a more open and lengthier selection process. Speed has its costs. One of the problems with Rudd's replacement by Gillard in June 2010 was the breakneck speed at which it occurred.

One of the other possibilities touted was Aboriginal leader Warren Mundine, a former Labor president. Former Labor minister Barry Cohen is right to point out that a huge gap in Labor's federal ranks lies in its lack of indigenous representatives, given that the Coalition has already elected two indigenous federal MPs, including current member Ken Wyatt. Filling that gap should have been a high priority for Labor.

John Warhurst is an emeritus professor of political science at the Australian National University.

John.Warhurst@anu.edu.au