[The graph above] is not a perfect fit — this is economics, not physics, and anyway stuff besides the output gap bounces inflation around from year to year. But still, there’s a clear correlation, driven largely but not entirely by the deep slump and disinflation of the early 1980s, and an implied slope of about 0.5 — that is, every percentage point by which real GDP fall short of potential tends to reduce the inflation rate by about half a point over the course of the year.

And right now the CBO is saying that in the absence of a policy action the average output gap will average 6.8 percent over the next two years. Do the math: if anything like the historical relationship between output and inflation holds, we’re looking at major deflation.

OK, maybe that relationship won’t hold — getting to actual deflation may take a deeper slump than merely reducing the inflation rate. And maybe a regression driven in part by 80s data isn’t a good guide to current events. But deflation is a huge risk — and getting out of a deflationary trap is very, very hard.

We truly are flirting with disaster.