Rattenbury has done the Greens proud, or has he?

As new transport initiatives go, the car-sharing trail announced by Transport Minister Meegan Fitzharris on Monday is the equivalent of political small potatoes. With the allocation of 22 government-owned car-parking spaces located in the City, Dickson, Russell and near the Federal Treasury building in Parkes, the government hopes the two-year-long trial will encourage Canberrans to sample the joys of motoring without having to endure the bother and high cost of car ownership. Creating transport options for Canberra is how Ms Fitzharris puts it.

Apartment-dwelling, inner-city Canberrans who've forsaken car ownership but who occasionally have need to drive across town or to Sydney for the weekend will welcome the plan. But close on their heels (in terms of jubilation at least) will be Greens MLA and Labor coalition partner Shane Rattenbury.

In 2008, when he was but a mere Greens candidate seeking election to the Assembly, Mr Rattenbury was championing the desirability of car-sharing so that Canberrans could, if they wanted, avail themselves of a car from time to time without the "hassles" of ownership. Reid, Braddon, Turner and Ainslie residents would be ideal candidates for car-sharing trial, Mr Rattenbury pronounced at the time – mindful no doubt that these suburbs were and remain redoubts of Greens support.

Though he won election to the Assembly in 2008 (along with fellow Greens candidates Amanda Bresnan and Caroline Le Couteur), Mr Rattenbury must have figured that his chances of actually being able to implement a car-sharing trial – let alone fulfil the Greens' other major policy commitments like light rail – were negligible. Labor's electoral setback in 2012 changed that, however.

Handed the role of political king-maker, Mr Rattenbury chose Labor, not surprisingly. He drove a hard bargain, compiling a laundry list of nearly 100 policy initiatives which Katy Gallagher formally agreed to undertake on November 2, 2012.

The natural convergence of the Greens and Labor on issues like light rail notwithstanding, Mr Rattenbury has achieved perhaps close to 80 per cent of his and the Greens' goals, a notable achievement given the tribal nature of Labor politics. FOI reform and a needle and syringe exchange program remain perhaps Mr Rattenbury's biggest misses. Otherwise, his is an exemplary record of political achievement in relatively short order, marked, it has to be said, by an even temperament and sense of proportion which has rarely faltered.

The question that now arises is whether Mr Rattenbury's accomplishments will lead to Greens recovering the two seats they unexpectedly lost in 2012. While the voters of Kurrajong (which includes the inner north) look likely to bless Mr Rattenbury with a third term, there's a feeling elsewhere that his close cooperation with a tired and irritable Labor government, particularly on the contentious light rail project, may lead to a reduced Greens vote in other electorates.

This was always the risk, of course, with getting so wholeheartedly with Labor. Mr Rattenbury has furthered the Greens agenda, but in a way that makes him look like a Labor-lite politician.