This election has proven that financial inequality has become one of the most important issues to voters. Bernie Sanders has built his entire campaign around the idea and Trump has harnessed the fear of the disenfranchised to rally voters. Regardless of how candidates tackle this issue, it's clear that voters are looking for a change.

Political Science Professors Kenneth Scheve & David Stasavage have written the book, Taxing the Rich: A History of Fiscal Fairness in the United States and Europe, which looks at the taxing history of 20 different countries and what circumstances led to increases in taxes for the wealthy. The theory that their research led to is called, the compensatory theory of taxation. This means that the rich will receive higher taxes when they believe that the compensation they will receive from the state is greater than the increase in money they have to pay in their taxes.

For instance, Scheve and Stasvage’s study showed that tax rates were the highest around 1950, right after World War II.

“The argument here is that the political will and the willingness of wealthy citizens to pay higher tax rates was correlated directly with the draft and the war,” said Harvard Business School historian Nancy Koehn on Boston Public Radio. If lower and middle-class citizens are dying for their country, the rich are willing to pay a high tax rate.”

Koehn emphasized the importance of recognizing income inequality in this election and called it the most important election in the last 100 years. Koehn worries though that despite who wins the election, raising taxes on the rich will only happen  with the help of  Congress.

“It is all well and good to talk about it on the campaign trail, but there has to be a way to do that legislatively because the only folks that can touch the tax code are the folks in Congress, and they don’t seem to be able to do much of anything,” Koehn said.

Nancy Koehn is a historian at the Harvard Business School. You can listen to her interview with Boston Public Radio above