FDR was a social Democrat:

[Emile]

23. FDR realized capitalism needed a sprinkle of socialism to keep it in check.

That made him a man with compassion, and common sense.

A social democrat is an adherent of a political ideology that seeks to reform capitalism through democratic means, establishing a balance between a free-market economy and a comprehensive welfare state. The goal is to reduce inequality and provide universal social programs like public education, healthcare, and pensions.Core Philosophy Social democrats do not seek to abolish capitalism, but rather to heavily regulate it and tax it to ensure that wealth is distributed fairly. They champion "positive liberty"—the idea that people need basic material security and opportunity (such as healthcare and housing) to truly be free.

He never called himself a socialist, but he was willing to adopt socially democratic reforms. That in itself made him one of the greatest presidents in our history.