Department of "Huh?!": What Model Is Jeffrey Sachs Working in? Edition

Whenever I build a model in which expansionary fiscal policy fails to reduce unemployment, it is for one of three reasons:

Expectations of the present and future deficits cause the price level to jump now, so that increased nominal spending does not translate into increased real demand (i.e., Mitterand ca. 1981)
The expansionary effect of higher deficits is offset by higher interest rates that crowd out private investment and exports, offsetting the stimulative effect of the fiscal policy...