DONALD Dewar, in that patrician way of his, was airily dismissive of Alex Salmond when the two faced each other at First Minister's Questions. Jack McConnell used the weekly joust to wind up his opponents by referring to 'the Scottish Nationalist Party'. But that's about as far as routine, ritualistic Nat-bashing went in the early years of the Scottish Parliament. It's astonishing to recall, given the seismic changes since 1999, how the SNP was largely ignored.

Mr Dewar was busy managing the twin novelties of devolution and coalition government. Henry McLeish, his successor, worried more about Labour colleagues south of the Border (who frowned on his policy of free care for the elderly, for example) than he did the main opposition at Holyrood. Mr, now Lord, McConnell, lost sleep over the possible public reaction to initiatives such as the smoking ban, or twinning Scotland with Malawi. The SNP rarely troubled his dreams.

With 35 seats in 1999 and 27 on 2003, the Nationalists were largely an irrelevance - and they were treated as such.

Things are very different now, of course, but a distinctive feature of SNP government has been its constant focus on its opposition. Mr Salmond and Nicola Sturgeon devote far more time and energy to discussing Labour and the Conservatives than ever was the case when different boots were on different feet.

There are sound political reasons for this. While the Conservatives are in power at Westminster, the Scots Tories serve as a useful reminder of unpopular UK policies. As for Labour, the SNP are on a mission to crush a party that occupies the same centre-left territory and which still presents a significant obstacle to winning majority public support for independence. Glorying in Labour's not inconsiderable trials and tribulations makes a lot of sense.

But there are pitfalls, too, to maintaining such a relentless onslaught against opponents who struggle to land a glove on the First Minister.

For a start, the enthusiasm with which Ms Sturgeon and her ministers pursue opposition MSPs rather gives the impression they are happy enough to divert attention from their own record in government.

The tendency to thwack all criticism back in the direction it came from has been distilled, pithily but unappealingly, into "SNP bad".

SNP bad is one of the year's most striking phenomena. It began as a meme on social media, as Nationalists took to dismissing anything critical of or embarrassing for the SNP government as "SNP bad". It was eagerly picked up by tweeting MPs and MSPs and has now entered the political lexicon at Holyrood, trotted out by backbenchers and even ministers answering parliamentary questions. It's not a good thing.

A recent example shows why. Without rehearsing every twist and turn in the story of the Forth bridge closure, it's clearly reasonable to ask why it happened. Regular maintenance is supposed to stop bridges breaking, after all. But even before an explanation was provided, questions about the closure were ridiculed as an attempt to create an "SNP bad story". This particular SNP bad story was even given its own theme tune courtesy of party activists who, to the tune of London Bridge is Falling Down, penned an embarrassing ditty praising ministers for "fixing it quickly". The chorus went something like: "Let's all cheer for the Scottish Government".

SNP bad isn't just a way of deflecting questions or criticism, it's a way of mocking opponents who have the temerity to raise issues of legitimate concern. As such, it betrays a complacency bordering on arrogance and contributes to an infantilized political culture in which supporters and activists begin to resemble the fan base of a teen pop band.

I can't see it going away, so quickly and easily has it become part of the glue that binds Scotland's most powerful political tribe together. But I don't think it augurs well for a year in which, barring something extraordinary, will see the SNP back in government with an even bigger majority. Ms Sturgeon will wield more power than any of her predecessors, especially when responsibility for tax and welfare are transferred to Holyrood as a result of the new Scotland Bill. Proper scrutiny will be more important than ever. If the Nationalists choose to cry "SNP bad" rather than engage in debate, policy-making will be poorer for it.