The launch of the SNP manifesto was yet another polished, confident performance by the party's leader Nicola Sturgeon.

Five years ago, the star of the general election was the Liberal Democrat leader Nick Clegg and his rivals were clamouring to agree with him. This time around, none of other leaders is willing to say "I agree with Nicola", but equally none of them has been able to even dent her campaign.

The message delivered in the manifesto was the one that Ms Sturgeon promoted during the referendum and again during the leaders' television debates - that there is an alternative to austerity based on more public spending and higher tax. But if you look closely, there were also some subtle adjustments to the language used to deliver the message that offers a few clues to what might happen immediately after May 7th and in the five years of the next government.

At one point, Ms Sturgeon listed the revenue-raising measures she would support: the reintroduction of a 50p top rate tax, a tax on bankers' bonuses, a mansion tax, and the abolition of non-dom status. Until recently, the SNP was refusing to commit to the reintroduction of the 50p rate, but combined with such public backing for other high-profile Labour policies such as the end to non-dom status, supporting the 50p rate now is another way for Ms Sturgeon to make it increasingly difficult for Ed Miliband to reject any kind of arrangement with the nationalists in the event of a hung parliament.

There was another subtle change in the SNP language which may indicate an adjustment to Ms Sturgeon's intentions. The party has been vehemently calling for full fiscal autonomy, ie control of all taxation raised in Scotland as well as the revenues from North Sea oil, but in the manifesto the wording has changed from "full fiscal autonomy" to "full fiscal responsibility". That might look like a subtle change but combined with the fact that Ms Sturgeon appears to be extending the timetable with talk of fiscal responsibility happening in several years rather than next year, it looks like a tacit acceptance of the economic difficulties involved.

The most obvious of them is the price of oil. The referendum was fought when the price was still high, but it has slumped ever since and the SNP knows that it must adjust to the new reality. It has also not found any easy way to bat away the estimate by the Institute for Fiscal Studies that full fiscal responsibility would leave Scotland with a £7.6bn shortfall. The black hole is still a black hole.

Part of Ms Sturgeon's response is an anti-austerity message based on more public spending that Labour rejected for fear that it would go down badly in England. When Ed Miliband launched his party's manifesto earlier this month, he committed his party to a so-called Budget Responsibility Lock, meaning that every policy in the manifesto would be paid for without any additional borrowing, but the problem is that the message does not appear to be working in Scotland.

Instead, Ms Sturgeon's message is that there should be "modest" extra public spending and her promise is that any borrowing would be part of a continuing programme to reduce and pay off the deficit. On the face of it, such a policy looks very different from Labour's Budget Responsibility Lock, but the SNP's plans are for spending to increase by only 0.5 per cent per year. That means that the SNP and Labour are much closer on the economy that they might first appear, especially compared to the Tory plans for more and deeper austerity. The SNP's manifesto has reduced the distance from Labour every further.