Since 1938 the Democrats have held the White house for 35 years, the Republicans for 34. Over that time the national debt has increased at an average annual rate of 8.7%. In years Democrats were in the White House there was an average increase of 8.3%. In years the Republicans ran the White House the debt increased an average 9.7% per year. Those averages aren’t that far apart, but they do show a bias toward more borrowing by Republicans than Democrats even including World War II.
If you look at the 59-year record of debt since the end of WWII, starting with Truman’s term, the difference between the two parties’ contributions to our national debt level change considerably. Since 1946, Democratic presidents increased the national debt an average of only 3.2% per year. The Republican presidents stay at an average increase of 9.7% per year. Republican Presidents out borrowed and spent Democratic presidents by a three to one ratio. Putting that in very real terms; for every dollar a Democratic president has raised the national debt in the past 59 years Republican presidents have raised the debt by $2.99.