The authors of this study find that estate taxes, and the rates they are set at, come and go with war - natoable the bog ones that require a high level of sacrifice across the board. The same argument applies to progressive tax rates. The less wealthy were subject to the draft - that was their sacrifice. The estate tax was intended to equalize sacrifice:
Our research identifies the political reason that estate taxes, and taxes in general, became more progressive in countries that mobilized for war. Proponents of progressive taxation made a clear case that if the broad population was to sacrifice for the war effort, then on grounds of fairness the wealthy should make a financial sacrifice to pay for the war. During World War I this came to be known as “the conscription of wealth,” a turn of phrase arguably as impressive as “death tax,” in contemporary debates. Likewise, during World War II, President Franklin D. Roosevelt and American labor unions made use of the term “equality of sacrifice” to call for heavier taxes on the wealthy. Since war debts continued after each war’s end, these two terms retained their salience even after conflict had ceased.
A striking illustration of our fairness argument can be gleaned by using the Google Ngram Viewer. This allows users to scour the archive of full-text searchable historical documents to see the frequency of specific phrases. Since John Stuart Mill’s use of the term in 1848, “equality of sacrifice” has been one proposed criterion for judging whether a tax system is fair. By the late 19th century, many economists argued that equality of sacrifice could be assured only if the wealthy were taxed more heavily than the rest. Each dollar in taxes represented a smaller sacrifice for the rich than for the poor. Nevertheless, the Ngram’s evidence shows that “equality of sacrifice” gained real salience only with the advent of the First World War, seven decades after the term’s introduction. See the graph:
