The coalition government has lost its way after the burst of policy in its first 100 days. So Jacinda Ardern's return this weekend signals a key moment in its life... and its path to 2020

Jacinda Ardern returns to Wellington and the full-time job of Prime Minister this weekend carrying not just bags of baby gear - and a new baby - but a whole bundle of political capital.

On any sort of personal level, the past six weeks will have been first and foremost a time to adapt to parenthood and fall in love with her new child. But Ardern is a political creature to her bones. As she told John Campbell on Checkpoint today, she did not stop being Prime Minister really. And anyway, the role isn't a job, it's an opportunity. It's been her life for more than a decade.

So Ardern, as careful as she is to show us just how much like the rest of us she is, would surely have spent some of these precious six weeks making the most of some rare distance from the political fray, reviewing her government. After so long on the field, some time watching from the stands would have been informative. What will be interesting as she jogs back onto the pitch is how she chooses to play the game between now and Christmas. 

She comes with bundles of goodwill, baby love and support, all of which combine to create some serious political capital. The question is how she will choose to spend it.

The Labour-led government (as much as Winston Peters dislikes that phrase, he's not PM any more!) has had two phases in its short life. Scene one was its first 100 days. Through these weeks it looked like a government with a purpose and it achieved alot. Its mini-Budget delivered its keystone and most expensive policy - the Families Package, estimated to raise the incomes of 384,000 families. We got the winter heating, Best Start payments for babies, a foreign buyers ban and the Pike River Recovery Fund, for example. Perhaps most under-sold of all, contributions to the Super Fund resumed and a new independent office to cost party policies.

Labour's problem, however, is that it was all under-sold. The communication around that first 100 days was woeful and most New Zealanders hardly noticed what was a significant tranche of policy reform.

In the days after - scene two - the government rather lost its way. Labour's plans for "transformation" that went beyond the 100 day list seemed to lack detail. The time spent bickering in Opposition seemed to catch up with it and its lack of thorough policy work was exposed. Suddenly they were all talk, no trousers. The biggest decision of all - to draw a line under oil exploration - was rushed and poorly executed.

The Greens muddled through their leadership race and James Shaw seemed to run out of steam and disappear. New Zealand First rediscovered its quixotic and combative sides. It all looked a but messy. But Ardern's pregnancy blanketed it all.

New baby Neve will buy the government more time; perhaps the rest of this year, perhaps (Simon Bridge's nightmare) the whole first term. But Ardern can't rely on that. She has to find a new gear for her team, to shake them out of their complacency and start delivering on expectations. 

Ardern has joked that she has not yet found a routine with baby Neve. She must at least hope she can get some with her ministers.

So where should she - and they - focus? We know from her weekend Facebook post that her first week back involves announcements or work around - mental health, environmental issues, trade-related matters, employment. 

Newshub tonight has revealed that the latter announcement will be a long-promised dole for apprentices scheme, whereby employers willing to take on people on the Jobseekers benefit will get paid that benefit. It's policy that dates back to Phil Goff's leadership and it's sound. It should be popular. 

Perhaps the more pressing question will be what Ardern announces on the trade front, something Stuff reports she's due to unveil after cabinet on Monday. As much as Ardern will be lured to undoubtedly important environmental and health issues, she needs to understand the issue right in front of her - the one which she could yet trip over - is the economy. Of course it is, stupid.

Spending her capital on social issues will deliver a low return on investment. The real gains at this stage of the cycle are to be made in economic policy. These are hard issues to deliver rapid change on, but her political capital would be best spent in the realms of infrastructure, immigration and, sure, trade. She needs to be a mama with a bulldozer.

Yes, business confidence surveys are a kind of passing beauty contest and beauty is in the eye of the beholder. And, no, this isn't a winter of discontent a la 2000. Business is not as hostile or organised. A low dollar, reasonable commodity prices and increased spending are all good signs. But Labour still has much to do to convince business leaders - and even smaller business owners - they are a safe pair of hands. 

Newsroom has helpfully pointed out too, why there is reason to be wary: unemployment up for the first time since 2016, two construction firms toppling, and house prices falling nationally. There's also the spectre of strike action in two major sectors - health and education. 

Ardern has promised a major speech on the economy within a month, and it is sorely needed. Labour needs to rediscover its sense of purpose and direction, and economic issues have to be at the core of that. It's probably too much to hope that it will finally acknowledge the need for new borrowing to tackle the infrastructure drought. That would be the smart place to spend her political capital

But it must at least start setting the agenda again with not just schemes and working groups, but practical policy. It needs to show confidence and competence. 

Frankly, with Ardern's return the government needs a reset. It needs to stop drifting and get down to business. These next few months, as Ardern returns to scene three and with the political glow of pregnancy behind her, will be crucial. In many ways the 2020 campaign begins now.