"A principle isn’t a principle until it costs you money", wrote Bill Bernbach, generally acknowledged to be the greatest adman of the 20th Century (which readers of the New Statesman may not necessarily view as the most worthy of monikers, but you’d have to admit, he knew how to turn a phrase ).
It’s a sentiment that I suspect Ed Miliband would concur with. And more to the point, I suspect the public would concur with. If Labour can show they have made a decision that will cost them millions  – and they'd better be sure that the New Statesman is right on that , and that the FT is wrong - then the public will reward them for a principled decision. And how deftly Ed Miliband has turned the tables on Cameron, who now has to make some pretty tough decisions himself on party funding and second incomes for backbench Tory MPs (and if he does ban the latter, you’d suspect a few more letters  will be heading Graham Brady's way).
But where does all this leave Nick Clegg and the Lib Dems? The answer is - facing both an opportunity and a threat. Being perennially stuffed for cash, made much worse by the removal of short money when we went into government, funding reform has been high on the priority list for the Lib Dems for some time. It seemed that the chance to do something about it this parliament had gone – but now suddenly it’s back on the table again, an opportunity Nick Clegg was quick to point out in DPMQs yesterday .
More than that, Nick’s spotted a bit of an opportunity too; why not, as part of the 'opt-in' system let union members name the party they would like their political levy to go to? For example, the majority of Unite members don’t vote Labour.  It's quite a thought isn’t it, Unite, Unison and the GMB posting off cheques on behalf of their members to the Lib Dems, the Greens, the Tories…
However, there are downsides to this wheeze; when one party is in the process of costing themselves a fortune on a point of principle, trying to instigate a get rich quick scheme may not play well to the gallery. In fact, you look like a bit of an ambulance chaser. Especially when you have a Michael Brown- shaped rock  your opponents can throw back at you.
Far better, I think, for Nick to take the high ground and form an alliance with Labour on party funding reform, shaming the Tories into action. To quote Bill Bernbach again: "If you stand for something, you will always find some people for you and some against you. If you stand for nothing, you will find nobody against you, and nobody for you".
Nick should leave the tactical stuff on party funding to the troops and go climb the high ground with Ed. After all, who knows where such teamwork may lead…