Alan Auerbach and Yurij Gorodnichenko have a nice piece over at Vox which reports empirical evidence that the size of the fiscal multiplier in the US is not constant over time, but varies over the business cycle. During good times, it is small — between 0 and 0.5 — while during recessions it is high — between 1 and 1.5. (During depressions it is even higher.) This is of course exactly what we teach our undergrads in standard macro courses (at least, I think of them as standard macro courses, but I guess not everyone agrees nowadays): here is more evidence consistent with those models.
Recessions are not a good time to have to cut government expenditure. They’re an even worse time to cut expenditure if you don’t have to.