Paul Kedrosky posts the following chart showing government debt to GDP across various key (and not so key) countries).

The first thing that stands out, obviously, is Japan. We'll come back to that in a minute.

Then you notice that government debt-to-GDP in the US is still lower than Italy, and only modestly higher than the UK and Germany.

It stands to reason that if you're worried about the US debt situation, and a possible blowup here, we'll probably see blowups in countries like the UK and Italy before then, and that if such a situation occurred, we'd see a flight to safety (the dollar), further delaying any possible day of reckoning.

After all, it's hard to imagine a world where lenders lose confidence in the US before losing confidence in Italy and the UK (UK's marginally lower government debt is offset by the outsize scale of its financial sector, and the cost of bailing it out. Remember, post-crisis, we know that financial sector debt = government debt).

As for Japan, yes, it looks like the bond short-sellers dream candidate for a blowup. Once again though, it all depends on whether it matters that their debt is externally or internally financed. If you think they're one and the same then yes, Japan looks to be screwed.

If however, you think internal financing is inherently safer, because where else are the Japanese going to put their money, then the famous anti-Japan bet will probably fail once again.