The global financial crisis followed an extraordinary upward swing in the leverage cycle (Geanakoplos, 2012). When the bubble burst, the massive debt accumulation in the private sector sparked a typical debt deflation dynamics (Fisher, 1933, Minsky, 1982) that propelled the ratio of public debt-to-GDP very rapidly reflecting on one side the recession-induced decline in government revenues, and a fall in the level of prices-including those of assets; and on the other side, governments actually taking over private debt gone sour. Late empirical studies have started to focus increasingly more on the relationship between private debt and the macroeconomy (Jordá et al., 2014; Taylor, 2012; Schularick and Taylor, 2012). The key takeway from this body of work is that credit growth predicts financial crisis and that, conditional on having a recession, stronger credit growth predicts deeper recessions (Mian and Sufi, 2014; Glick and Lansing, 2010). Theoretical economic modeling has flanked the empirical research, at least up to a certain point. Building upon the modern model-based literature on collateral and leverage cycles going back to the mid-1990s pioneered by Bernanke and Gilchrist (1995) and Kiyotaki (1997), a number of recent papers in macro-finance have focused on how to reproduce ways in which excessive indebtedness in the private sector can harm the economy. None of these models, however, explores the macro-financial links between private and public balance sheets, or the dynamic interaction between fiscal and private agents during leverage cycles, which so distinctly characterized both the evolution and the recovery phases of the recent crisis. Similarly, models which do incorporate a developed public sector, and study the borrowing constrains of the government deriving the maximum government debt-GDP ratio that can be sustained without appreciable risk of default or higher inflation, do not model the role of the government as a fiscal actor or as a lender of last resort during protracted phases of financial stress. In this paper we focus explicitly on these links. We start by revisiting empirically the interaction between private and public debt in affecting economic growth. While we reaffirm the empirical result that public debt does not generally exacerbate financial recessions, we also confirm empirical existing results that there are important nonlinearities at play between public and private debt during the deleveraging phases of leverage cycles, implying that public debt impact on financial recessions changes depending on its level. We then build a parsimonious analytical model capable of stylizing this trade-off by embedding in the model links between private and public debt dynamics. The basic model structure follows Kiyotaki (1997)'s model of credit cycles that shows how small shocks to the economy might be amplified by credit restrictions, giving rise to large output fluctuations; and it embeds Iacoviello (2005)'s modifications to replicate features of borrowing constraints in the housing market within a New-Keynesian setting. Our model accounts explicitly for the two key links between private and public indebtedness that characterize debt deflation dynamics. Consequently, it is able to reproduce well two main findings of the recent empirical literature, namely that higher levels of private leverage lead to more severe recessions, with more serious consequences for public finances; and that an adverse fiscal position, either initially or caused itself by a severe financial recession, exacerbates the downturn because of the lack of fiscal space to stabilize the economy. [ABSTRACT FROM AUTHOR]