"The 1946 high was prompted by a spending push to fund World War II, and other spikes in the debt have been driven by economic downturns. But the current bump comes amid a relatively healthy economy, suggesting a structural gap between how much the country collects in taxes and how much it spends.
The “debt to GDP” measurement compares the overall amount of debt held by the federal government with the size of the entire American economy. Economists use the comparison to illustrate the scope of the deficit, providing a comparison that takes into account inflation and overall economic growth.
The long-term deficit analysis CBO released Tuesday goes beyond its typical assessments of budget outlooks within the next decade. The analysis makes clear that the deficit projections are impossible to gauge with complete precision, in part because it cannot account for unforeseen changes to federal policy, economic trends or global events.
The CBO projects the Republican tax law passed last fall will add $1.84 trillion to the federal deficit over the next 10 years. Republican leaders have argued the cuts will jump-start the economy, creating enough economic growth to offset much of their additions to the debt. But CBO and other nonpartisan analysts have repeatedly rejected that claim."