If you'd told me a week ago that Alex Salmond would be offering to go into coalition with Labour, I'd have disbelieved you. Yet that's just what he's done; offered to go into a rainbow coalition with Labour, and with an admonishment to the LibDems that they should follow suit.
Is he serious and will he follow through? The answer is yes to both - but I suspect like most of us he thinks a Con-Dem'd govt is more likely. So what is the reasoning behind his offer?
He's laying down a marker. He's letting Scottish voters know that he tried everything to prevent a Tory government, and if they get one anyway, it's the LibDems to blame. Plaid Cymru quickly followed, and the DUP made a statement about supporting whoever maintained their block grant (something they got from the Labour government, but which Cameron specifically threatened in his interview with Jeremy Paxman).
The LibDems have 11 seats in Scotland, and all will come into play if they ally themselves with the toxic Tories. They have three seats in Wales, and two seats in the North-East (another place singled out specially for cuts by the Tories), and all these will come into play too.
Basically, the word will go out in England, Scotland and Wales that if you wish to keep the Tories out, voting LibDem is not the way to go.
I have said in previous posts that coalitions are tricky, because one party always obliterates the other. Given the weakness of the LibDem performance in the election, they might be the ones for the chop at the next election, which may be as near as six months away.