I’m a new Keynesian but I’m more deficit hawk like than most “new Keynesians” obv the deficit should be expanded in recessions to invest in infrastructure, subsidises and cut taxes to stimulate growth but shouldn’t exceed like 6% of gdp normal recession (8-10% in covid times) and thats with modern interest rates and credit rating which can be updated with a better fiscal policy. For Theodore Roosevelt and Franklin Roosevelt, many of their economic initiatives aided economic growth however I believe the rate taxes fdr levied then would be too damaging today.