The article explores how the cost of a country defaulting on its debt can actually increase the likelihood of default. They found that high default costs can lead to lower bond prices and create fiscal limits not based on economic factors. The researchers suggest that private investment behavior plays a crucial role in government debt sustainability. Depending on investor expectations, there can be multiple equilibria where either investors expect default and low returns, or they are optimistic and invest more, leading to higher chances of debt repayment.