You would be forgiven for believing that the SNP is genuine when it calls, as it so often does, for more powers for the Scottish Parliament.

Long before Alex Salmond led his party to its first Holyrood victory in 2007, he and his colleagues were adamant that without the necessary “economic levers”, politicians in Edinburgh simply couldn’t do what needed to be done to make Scotland a more progressive, more successful country. The devolution settlement simply wasn’t good enough.

In power, the nationalists continued – and still continue – to demand greater freedom for ministers to make decisions on how money is raised and spent in Scotland. Our priorities, you see, were unique. Where Westminster was the home of the callous decision, Holyrood was populated by kinder, more thoughtful people. If only they were able to express this in their actions.

When Scottish Labour urged the SNP to mitigate the impact on claimants of Tory-imposed benefit limits, the response from Justice Secretary Humza Yousaf was as shrill as it was incoherent. Picture: Andy Buchanan/AFP/Getty Images

So successful was the SNP in its push for a more muscular parliament that a number of powers have, indeed, been transferred from Westminster to Holyrood in recent years.

And so it stands to reason, then, that the nationalists would use those powers to address the issues it feels most strongly about.

Anyone who has paid the slightest bit of attention to Scottish political debate in recent years might consider the UK government’s policies on benefits to be at the top of that list. SNP politicians have been relentless in their criticism of Tory “austerity”, attacking policies on benefits as cruel and inhumane and – of course – insisting that an independent Scotland would do things differently.

The controversial two child benefit cap and the so-called “rape clause” – which requires women who may have had a child as a result of rape to declare as much if they are to win an exemption from the new limit – have been held up, not unreasonably, by Scottish nationalists as examples of how the Conservatives can get things terribly wrong when it comes to social security.

Yet, despite the SNP’s oft-declared opposition to these policies, ministers seem curiously unwilling to use the powers they have at their disposal to do anything about them.

Last week, Scottish Labour leader Richard Leonard called on the SNP to think again and use its hard-won authority to mitigate the impact on claimants of these benefit limits.

Leonard suggested the Scottish budget, to be unveiled on 12 December, should allocate around £70 million to reverse these controversial policies.

The reaction from nationalist politicians was as shrill as it was incoherent.

“When I hear ScotLabour’s demands for us to continually mitigate Tory policies (at a high price), instead of actually having powers to prevent such disastrous policies,” tweeted Justice Secretary Humza Yousaf, “I find it hard to comprehend how it’s possible to have such a lack of ambition, both for yourself & your country.”

Sure, the SNP at Holyrood has the powers to overturn Tory policies it claims to despise but isn’t the real problem the fact that Labour suggested it should use them?

Even the SNP’s own growth commission says that the early days of independence – should it ever become a reality – would come at a cost. How the necessity for further cuts created by Yousaf’s “ambition” would make it easier to “prevent such disastrous policies” is one for smarter people than I.

The fact is, of course, that the SNP could quite easily use the powers at its disposal to do what Leonard suggests. Instead, ministers allocate millions to populist policies such as free university tuition fees and free prescriptions for all, both of which disproportionately benefit the well off.

Suggesting that the Scottish Government use its powers to help the most vulnerable is bad. Using those powers to benefit the middle classes – those most likely to turn out and vote in Holyrood elections – is good. Don’t you see?

We should be grateful to former SNP MSP Kenny MacAskill who has, in the past, provided some insight into the cynicism that can lie behind decision making at the highest level in the Scottish Government.

Three years ago, he wrote of his complicity, as the former Justice Secretary, in the wrong-headed decision not to allow prisoners the right to vote, despite a European court ruling that excluding convicts from participation in elections breached their human rights. MacAskill admitted that this decision had been taken not because of any principled position but because ministers feared controversy that might harm the nationalists’ referendum campaign.

“It was,” he wrote, “the wrong thing done, albeit for the right reasons.” The “right reasons”, then, were about protecting the SNP from the need to take a potentially controversial position.

And so we know that, for all its talk of being progressive and outward looking and all the lovely things it claims characterise it as a party, the SNP has no problem at all with prioritising whatever suits its independence agenda over whatever ministers believe to be morally right.

When it comes to increased powers for Holyrood and their use, the SNP has a selective approach.

Win the power to give free tuition fees to the offspring of lawyers in Bearsden and Morningside and it is right to use it. Win the power to mitigate the “rape clause” and it is wrong to do anything.

But then, for all their talk of radicalism, the SNP is as conservative as they come when it comes to deeds. There are more votes to be won by giving to those who’ll turn up at the polling station every four years than there are to be gained by giving to those trapped at the bottom of society.

Just as the SNP denied prisoners the right to vote because it feared such a move might harm the independence campaign, so it gives to the middle classes in the hope more of those Scots will join the Yes movement.

This is perfectly sensible politics. In order to reach one’s objective, one should deploy whatever powers one has in the most politically beneficial way possible.

So spare me from the line deployed by Humza Yousaf and others that asking the SNP to use the powers it has to tackle the problems it claims to prioritise is somehow a sign of a lack of ambition.

Euan McColm: Selective use of powers shows where SNP's true priority lies