4. George W. Bush (2001 to 2009)
President George W. Bush added about $4 trillion to the U.S. national debt.18 Military spending increased to record levels under Bush, due to launching the war in Afghanistan and War on Terror in response to the September 11, 2001 attacks, as well as the Iraq War in 2003. Additionally, Bush supported and signed into law significant tax cuts which contributed to increases in national debt. Bush and his administration also dealt with recessions in 2001 and 2008 (the Great Recession).2021