For years, the Lib Dems have struggled with the accusation of ‘irrelevance’. They have pointed out quite rightly that smaller parties struggle against an electoral system which works against them, and media which give most of the attention to the two big parties.
For Nick Clegg to now lay into the SNP leader  as "irrelevant" and a "two bit player" smacks of double standards. Nether does it do anything to encourage respect, or aid the development of a ‘new politics’. But the most important point is that it perpetuates an arrogant narrative also held by the two big parties, which suggests that smaller parties have little of value to say.
It may be true that under a first past the post system many smaller parties have little chance of gaining seats - but of course the SNP has done so in Scotland despite this, as have Plaid in Wales. The Greens too may even gain one in Brighton.
But even if they didn't gain seats, they would not be ‘irrelevant’. Smaller parties provide an alternative and a choice for around 10 per cent of the voting population. They might also provide a home for many of the 30-40 per cent of the population who won’t vote at this election, if only the system became more proportional (as the Lib Dems propose) and their votes counted.
They might even attract a few Lib Dem voters too.