If this works out, Brown'll go down in history as the man who facilitated the transformation of UK politics... by performing just badly enough to produce a hung parliament in the election (but not so badly that DaveCam became PM).
On the other hand, if a coalition is formed but falls apart before PR can be passed, or if they call a referendum that fails, it's probably game over for the left in Britain for a generation.
This is high-stakes political poker but I'll be f***ed if it isn't exciting.
I don't know... I still think minority Tory govt or a loose Lib Dem-Tory governing deal are the safest options for Labour - but if this rainbow thing does come off, I'll be very glad to be proved wrong.