* Inflation: Comparing spending across decades requires adjusting for inflation. A dollar spent in the 1960s is worth far more than a dollar spent in the 2020s. Raw spending numbers are misleading without inflation adjustments.
* Definition of "Education Spending": The federal government funds education in many ways, through different departments and programs. Some administrations may emphasize direct grants to schools, while others prioritize things like research grants or student loan programs. The definition of what counts as "education spending" affects the results.
* Data Availability & Measurement: Historical data on federal spending is not always consistently categorized or readily available in a way that allows for easy comparison across different presidencies.
While some presidents like Lyndon B. Johnson are associated with major expansions of federal education programs (e.g., the Elementary and Secondary Education Act), determining who spent the *most* requires a sophisticated analysis controlling for inflation and consistent definitions, which is beyond the scope of a simple answer. Such an analysis would require considerable economic and historical research.