Eventually they choose to provide a lot of guarantees, print a lot of money, and monetize a lot of debt, which lifts the economy into a reflationary deleveraging. If they do these things and get the mix right quickly, the depression is much more likely to be relatively short-lived (like the short period of “depression” following the US crisis in 2008). If they don’t, the depression is usually prolonged (like the Great Depression in the 1930s, or Japan’s “lost decade” following its bubble in the late 1980s).
