But the Greens are going through struggles common to small parties working in close proximity to a larger frenemy on the same broad ideological side.
With an election campaign to start and polls pointing to a coalition government, strategic pressures will intensify.
The Greens aren't in coalition with Labour but Shaw is a minister holding a key portfolio for both parties.
As competition for voters concerned about the same issues heats up, a smaller party has to stake out distinctive territory. Its ideas can be absorbed or batted away. If voters know the election will be close, some might be less inclined to vote-split to help the potential junior partner.
The small party has to convince it can be both constructive and influential, while being a credible watchdog over its bigger rival on what matters to its activists and supporters.
It has to play to different audiences: the general, independent voter and the more emotionally invested party faithful.
Then there's the bigger picture. Polls have shown a tight race between left and right blocs for months and it's hard to see that changing. Coalition government is highly likely but the question is, which side?
As the Government, Labour needs to appear as a stable, competent manager, putting out fires while advancing its agenda and hoping for an upturn. National, with the support of Act, needs to present itself as a credible, stable alternative and a change of direction.
Neither main party wants to be undermined by a coalition partner that may be viewed as too erratic by voters in the middle.
Prime Minister Jacinda Ardern yesterday stressed continuity - Shaw would remain a minister - and stability during the Green Party's changes - ministerial roles aren't attached to co-leadership.
Gaining or holding voters' trust and confidence on the economy, crime, health and where the country is headed will be key in challenging times.
Shaw long seemed able to navigate public and party sensitivities in the manner of European Green politicians used to government roles. But some party activists appear to have faulted him for leaning into consensus and not being independent enough for their liking.
This can come down to differing views on how best to achieve change: by exerting outside pressure or working from within political power. On climate change some see it as now a completely mainstream concern that requires action from all sides while others view it in adversarial terms.
Labour's mostly cautious, by-the-book style of leadership on various issues, would have frustrated a lot of people who don't think the country has moved quickly enough on reforms, even as others believe it's travelling too fast.
Motivated groups of people opposed to various government actions have shown that they can grab attention.
Previous demonstrations in cities by rural activists, the protest outside Parliament, and the marches linked to Destiny Church suggest it could be a loud and disrupted campaign with discontent on streets, as well as within political parties.
