evidence: If current laws governing taxes and spending generally remained unchanged, federal deficits would continue to be large by historical standards from 2020 through 2030 and beyond, the Congressional Budget Office projects (see Figure 1-1). As a result of those deficits, federal debt would rise each year, reaching a percentage of the nation’s output that is unprecedented in U.S. history. [...] To put debt on a sustainable path, lawmakers will have to make significant changes to tax and spending policies—increasing revenues more than they would under current law, reducing spending below projected amounts, or adopting some combination of those approaches. [...] Future deficits and debt are likely to differ from CBO’s current-law projections for a number of reasons. Changes to laws and administrative actions—particularly those affecting fiscal policies—that cause them to differ from the laws and policies underlying CBO’s baseline projections could lead to budgetary outcomes that diverge considerably from those in the baseline.