evidence: As Democrats and Republicans girded for battle over the nation’s debt limit, President Joe Biden sought to tag his predecessor, Donald Trump, with a significant share of the blame for the nation’s $31.4 trillion federal debt. The U.S. debt has been collecting for over 200 years, and "one-quarter of that debt was accumulated in the four years of my predecessor," Biden said during a Jan. 20 event with the U.S. Conference of Mayors. Biden also touted actions on his watch to cut the yearly deficit by hundreds of billions of dollars, setting up a contrast with the debt on Trump’s watch. [...] Part of the reason Obama’s figure is so much larger than Trump’s is that he served eight years, while Trump served only four. So, if you divide the debt accumulated during each president’s tenure by the number of years they served, Biden, with only two years in office, has seen the largest rise in debt, with Trump second and Obama third.