Alex Salmond's speech in Aberdeen today was the first substantial intervention by Scotland's first minister since the independence debate got dramatically real last week. Mr Salmond had to respond to two large challenges to his independence strategy that have shaken up the debate about Scotland's future. The first was the chancellor George Osborne's declaration last Thursday, backed by both Labour and the Liberal Democrats, that a currency union with the remaining UK would not be on offer if Scots vote yes to independence in September. The second was the comment by the European commission president, José Manuel Barroso, at the weekend that it would "extremely difficult, if not impossible" for Scotland to join the EU after a yes vote. Since Mr Salmond's stance is that both the currency union and EU membership are desirable and achievable, the Aberdeen speech was a major test for the nationalist leader.

It is a test that Mr Salmond failed. His speech was typically combative and personalised. It contained the usual trenchant phrasemaking that makes Mr Salmond such an effective politician, especially with those who already support him. But at its heart was a failure to recognise that the challenges posed by Mr Osborne and Mr Barroso were meant seriously and had to be addressed as such. Since there could hardly be two more serious warnings, this was a misjudgment. By not taking the two challenges seriously, Mr Salmond risks appearing reckless, just when he needed to sound a reasoned and reassuring note. Scots voters surely cannot afford to be so cavalier when their future is at stake.

The first minister's response to Mr Osborne was particularly reckless. There is no point in a currency union unless both sides want to make it work. But where is the evidence that the SNP wants such a thing, with all that it entails, on a stable and long-term basis? There is little sign of it in the endless claims, much repeated today, of London bad faith. There is no doubt that the SNP, and many other Scots, are angered at last week's outright refusal of a currency union. They have every right to be. But to reduce this issue to an allegation of bullying by London is frankly pathetic. It did the first minister no credit that he preferred to tweak Mr Osborne's tail rather than give the serious response that his words actually deserved.

The response to Mr Barroso was less personal, but hardly less facile. The EU has not been faced with a situation like the one that it would face if Scotland seeks to join as an independent nation. The outcome cannot be predicted with certainty, but it is an obviously delicate precedent. Much would be likely to hinge on whether Scotland was treated as a new applicant – in which case it might be required to adopt the euro and to join the Schengen agreement (which could mean border controls at Berwick) – or whether it is regarded as a co-inheritor, along with the remaining UK, of earlier opt-outs. The EU has been worrying about such issues for many years, and Mr Salmond is simply wrong to give the impression that membership on the SNP's terms would follow seamlessly.

That is not to dismiss the SNP's assertion that both a currency union with the UK and EU accession might in practice be negotiable after a yes vote. Either or both remain political possibilities if the SNP plays its cards right and if the remaining UK and the EU decide that such outcomes are in their interest. That would be more likely, for instance, if the vote for independence was overwhelming.

But it is not a done deal, and Mr Salmond did little to turn the argument his way today. He needs to recognise the economic and political weight of the Osborne and Barroso warnings. It is, of course, very possible that his combative approach and a dislike of the Tories may tip support his way in the short term. But it is also possible that the long-term effect of the recent dramas will be to force Scots voters to weigh the risks rather more carefully and realistically than Mr Salmond did in his latest speech.