Standard & Poor’s is getting nervous about Uncle Sam’s debt. Should anyone care? Even without jokes about the rating agencies’ performance during the great US structured debt debacle, the answer should plainly be “no”. Theirs is only an opinion, based on public data, with a one-third chance that action will follow within two years. Given the scale of the US’s public sector deficit, few could argue with the idea that rating agencies may soon have to start downgrading.

Hence, the financial world soon worked out that this was largely a symbolic move meant for an audience of politicians, not investors.

But that does not mean that it does not matter. S&P had a choice over its timing, and might have opted, as Moody’s did earlier this year, to muse publicly about the possibility of a downgrade without placing it formally on to negative outlook. As the tense issue of the debt ceiling is not mentioned in its formal statement, it is not designed to play into the immediate