WHEN the opposition party leaders, Labour, Tory and Liberal Democrat, urged Nicola Sturgeon to “get back to the day job” following the aborted independence referendum, the last thing any of them expected was that she would do precisely that. Last week, the First Minister reminded them that she's pretty good at the day job too. Her compendious and radical programme for government stunned press commentators, who've been dining out for months on the notion that “peak SNP” is past and that Sturgeon is tired, unpopular and bereft of ideas. Not on this showing, she isn't.

Her speech silenced many of her left-wing critics, who think the First Minister has been following in the centrist footsteps of New Labour. Sturgeon has clearly decided that trying to appeal to everyone means you appeal to no-one, and has taken this paper's advice in staking her ground firmly on the social democratic left. This will have electoral consequences. One wonders if the SNP will ever again dominate the north-east of Scotland ,where her predecessor, Alex Salmond, managed to hold a traditionally Tory-voting area over decades.

Mind you, the small print of the Scottish Government's document, A Nation With Ambition, shows that the legislative programme is not quite as radical as it first appeared. Some of the measures that won most praise are vague aspirations, such as the promise to “fund research into the concept and feasibility of a Citizen's Income”, or Universal Basic Income as it's usually called. Environmentalists may have heard Sturgeon promise to ban fossil fuel cars and vans in 2032, but the Scottish Government doesn't have the power to ban petrol and diesel. She only promised to “promote” the use of ultra-low emission vehicles, with “a target” of phasing out polluting vehicles eight years before the rest of the UK. Even the National Investment Bank, as recommended by the pro-Yes Common Weal group, is not a done deal. The Scottish Government has only committed itself to “begin work to establish” such a bank.

However, there was enough substance in the address to satisfy most people that Sturgeon means what she says. The deposit return scheme for bottles and cans was directed at keeping the Green Party onside, along with a new Climate Change Bill. Free sanitary products, extending free personal care to under-65s and lifting the pay cap on public sector workers were directed at the Labour public sector vote. Liberals and prison reformers will appreciate the move to phase out prison sentences of 12 month or less. The Education Bill, freeing head teachers from local authority control, is actually a rather Tory-sounding policy. But the stand-out from Sturgeon's programme, and confirmation that she intends to challenge the revived Corbyn Labour Party from the left, was her declaration on tax.

The Tory leader, Ruth Davidson, said that the “SNP is coming for the pay check of everyone earning less than £43,000”, and while the FM's statement said no such thing, it may well come to that. As Sturgeon has herself admitted, raising the top rate of income tax in a relatively poor country like Scotland will not raise much cash. There are only around 20,000 Scots earning over £150,000 and many will find ways to avoid paying the 50p “additional” rate if it is reintroduced. Around 400,000 Scots pay the existing higher rate, and they are already paying £400 a year more in income tax than they would in England, where the threshold has been raised from £43,000 to £45,000.

This leaves Scotland's 2.1 million basic rate taxpayers looking rather exposed. To raise serious money for public services, they are the ones who're likely to be required to dig deep. The polling evidence is that many will probably agree to do so, despite the fact that Nicola Sturgeon promised only last year that she would not raise the basic rate of tax in this parliament. The FM could argue that things like free personal care, free tuition fees etc, constitute a “social wage” that is to the benefit of all and should be paid for by all.

To pre-empt charges of electoral dishonesty, she has apparently made any tax increases conditional on the support of other non-Tory parties. The programme for government only commits to “launching a debate” on the options. But there is no doubt about the FM's intentions. She wants to force the Scottish Liberal Democrats and Labour, who have been urging her to use Holyrood’s new income tax powers, to put their money where their mouths are.

It is important to remember, as this debate begins, that the tax powers granted to the Scottish Parliament by the 2016 Scotland Act were designed largely as a poison pill. No UK government would dream of raising the basic rate of income tax – the “toxic tax” – for fear of a voter backlash. Labour and the Tories in Westminster raise things like National Insurance, VAT, and fuel duties, dividend and wealth taxes – none of which Holyrood has the power to raise. This was no accident. Many in Labour and the Scottish LibDems, have urged Sturgeon to step into the “fiscal trap”, as it's known, in the sly expectation that it would destroy the SNP at the ballot box.

It will be interesting to see whether those parties who have talked the talk about tax are now prepared to walk the walk – or walk the plank as some see it. The favourite to lead the Scottish Labour Party in future, Anas Sarwar, has so far refused to say whether he will support the Scottish Government. But if he reneges on his predecessor, Kezia Dugdale's call for an across-the-board increase of 1p on income tax, then he will likely split his party. At any rate, Labour MSPs will no longer be able to accuse the SNP of being tartan Tories.

Sturgeon is right to make this a cross-party issue. She leads a minority government, which lacks the authority to drive through its plans on the strength of SNP votes in Parliament alone. This may be no bad thing: the 2007-11 SNP minority government under Alex Salmond was actually very successful in building a consensus for progressive policies. Nicola Sturgeon is eager to show that she can do minority government as well as anyone.

This was the first SNP programme since 2011 that did not focus on an independence referendum, but it didn't feel as if anything was missing. Sturgeon has made a virtue of necessity, and demonstrated that she can and will use Holyrood's devolved powers to the full – and that she will defend those powers. She is minded to follow the Welsh First Minister, Carwyn Jones, and pass a Continuity Bill to defend Holyrood's existing powers against the “power grab” from Westminster. Devolution is turning into a key issue in the Brexit debate and may have the capacity even to derail the EU Withdrawal Bill. Again, this means working with other parties to a common end.

Many thought that Nicola Sturgeon was incapable of moving on after indyref2, but move on she has. She's repositioned the Scottish National party firmly on the left and pledged to defend home rule. The onus is now on the opposition parties to decide whether to back her, or back the Conservatives and sack her.