The politics of Moody's credit rating for the UK
Just a few years ago - before the banking crisis - the international ratings agencies were barely mentioned in any political debate. At Westminster, most MPs would have struggled to name them. I suspect more than a few would have struggled to explain what the ratings agencies did.
Now a warning from one of the big three that it might, just might, downgrade Britain's credit rating in the next 18 months is enough to have the chancellor and his Labour shadow scrambling to offer explanations, and claim vindication for their economic position.
George Osborne has naturally seized on the fact that the report supports his efforts to reduce the deficit through spending cuts. It helps the chancellor that the report cites the crisis in the Eurozone as one cause of the economic slowdown - Labour has dismissed that argument as buck-passing.
More, Conservative Central Office has rushed out statements arguing Labour's plan to slow down spending cuts would make a credit downgrade unavoidable. The Moody's report says a downgrade could follow any "reduced political commitment to fiscal consolidation, including discretionary fiscal loosening".
But political argument is conducted mostly in sound-bites and slogans. George Osborne came to office inviting the country to judge his strategy harshly if the UK lost its "triple A" status. A lot has changed since then, but Labour's Ed Balls will not allow him, or the country, to forget that simple pledge.
Just as Labour may struggle to convince people that borrowing more is a sure route to cutting debt, so the chancellor may struggle to convince much of the the public that his spending cuts and tax increases are worthwhile, while the economy shrinks, and doubts hang over the UK's credit status.
There is little in this Moody's report to vindicate any rival strategy - including Labour's - but the coalition parties' hopes of winning the argument, and votes at the next election, were built on the prospect of eliminating the deficit and boasting of economic growth in time for polling day.
Now, those economic targets have been redrawn, austerity stretches ahead beyond May 2015, and the coalition's task of political persuasion looks tougher than ever.