Animosity like that on display in the current campaign has grown dramatically in recent years, say the authors – even while Americans’ views on the issues remain relatively moderate overall.

Republicans and Democrats “simply do not like each other to an unprecedented degree.”

That was one striking conclusion of University of Illinois political science professor Thomas Rudolph and co-author Marc Hetherington in their 2015 book “Why Washington Won’t Work.”

Animosity like that on display in the current campaign has grown dramatically in recent years, say the authors – even while Americans’ views on the issues remain relatively moderate overall.

So it’s about feelings much more than ideology: The opposing candidate is not just wrong, but often “cannot be trusted.”

Rudolph recently spoke with U of I News Bureau social sciences editor Craig Chamberlain about what it means:

You seem to be suggesting that the polarization in Congress has spread to the population and gotten personal. Is that the case? And, if so, what makes it so significant?

The U.S. Congress is highly polarized along partisan lines and has been for several decades. Although most scholars agree that polarization exists among elites, there has been a contentious debate among political scientists about whether the mass public is similarly polarized in its policy preferences. However, there is a growing consensus among scholars that average citizens are polarized in their feelings toward their political opponents.

Simply put, Republicans and Democrats increasingly do not like each other. This change is significant because such intense dislike can make it very difficult to achieve policy compromises in government. It is hard enough for Republicans and Democrats to overcome ideological differences in their policy preferences even when they like each other personally. When people strongly dislike and distrust their opponents, though, there is even less incentive for them to try to reach a compromise. A public that is also polarized can do little to rein in ideological excesses in Washington.

Why do you see distrust as so central to the current state of affairs in Washington?

The polarization of political trust along partisan lines is a critical reason why there is so much gridlock and dysfunction in Washington. When the majority party introduces a new piece of legislation, the minority party must be able to have some faith or trust in the majority’s promises about the future benefits of that legislation before it can support that legislation.

This is particularly true when the proposed policy conflicts with the minority party’s ideological principles. Members of the minority party are unlikely to sacrifice their ideological principles and support the majority members’ ideas if they do not trust those members personally. The growing polarization of political trust along partisan lines means that fewer people are willing to give the other party’s ideas a chance. In a world of divided government, such distrust makes it very difficult for Washington to pass much meaningful legislation.

We seem to be in a vicious cycle, with distrust leading to dysfunction, leading to voter anger and further distrust – even calls to elect whoever can “blow up” the system. What does your research suggest is at the root of it?

There is a growing feeling among many citizens that the federal government is out of touch and unresponsive to the needs and interests of average citizens. The continued rise of income inequality and a sluggish economic recovery have contributed to the belief that government is run for the benefit of moneyed interests in Washington and on Wall Street rather than for the benefit of common citizens. Such feelings have led to an increase in the number of Americans who are angry with their government.

Is there anything that might reverse the trend?

There is little evidence to suggest that the trend will be reversed any time soon, given the two major candidates in this year’s presidential election. Most Democrats do not agree with Donald Trump on most issues. That is to be expected. For many Democrats, however, opposition to Trump runs much deeper than mere policy disagreements. They intensely dislike him personally. In the eyes of such Democrats, Trump is not just wrong on the issues but he is an extreme and even dangerous candidate.

Similarly, Republican opposition to Hillary Clinton is grounded in more than simple ideological differences. Many Republicans see Clinton as a fundamentally dishonest politician who cannot be trusted to do what is right. Unfortunately, such personal animus toward the political opposition is not easily overcome.

Short of an unexpected national calamity, a reversal of this trend at the mass level will likely require significant and sustained changes in the political environment. It may require a much rosier economic outlook. It will almost certainly require a less polarized environment at the elite level in which partisan leaders engage in less hostile and less divisive rhetoric.

— It’s not just policy, many Republicans and Democrats have personal mistrust —