Questions about the legitimacy of the 2016 U.S. presidential election continue to reverberate and deepen partisan mistrust in America.

Doubts have been compounded by the indictment of 12 Russians following intelligence reports of Russian interference with the election. Reports allege the Russians used a variety of methods, including fake news, social media disinformation campaigns and attempts to gain access to state election records.

According to the indictment, Russians hackers penetrated the official voter registration rolls of several U.S. states, including Illinois. They stayed inside the voting system for several weeks before the 2016 presidential election, possibly gaining an opportunity to alter voter registration data and even vote tallies – although the Senate Intelligence Committee concluded that they did not actually do so.

Russian interference has exacerbated a toxic, partisan brew that has heightened concern about the election. Republicans allege fake news and massive voter fraud. Democrats fire back with claims about voter suppression and gerrymandering.

President Trump’s victory rested on the close outcome. The 2016 election turned on around 80,000 votes in three states. The Electoral College anointed the candidate who lost the popular vote. Partisan polarization has been further exacerbated by the American winner-take-all system, and Republican control of the legislative and executive branches of the federal government.

These challenges to electoral integrity in America are not novel. The contemporary fault lines first opened in the litigious wars over Florida’s ballots in Bush v. Gore in 2000.

Earlier decades, too, witnessed historic electoral battles over cleaning up Tammany Hall and Jim Crow laws in America. But the 2016 campaign highlighted several long-standing weaknesses and revealed new risks.

This atmosphere raises the question: How serious do perceived electoral flaws have to be to raise doubts not just about the process and results – or even the legitimacy of the declared winner - but about democracy itself?

Trust is way down

Not surprisingly, the last decade has seen plummeting American trust in the integrity of their elections.

The Gallup World Poll reports that in 2016 only 30 percent of Americans expressed confidence in the honesty of their elections. This is down from a majority of the public – 52 percent – a decade earlier. This is not simply the bitter fruit of the 2016 election nor is it a global trend. During the last decade, American trust in their elections has been persistently lower than many comparable democracies such as the U.K., Australia and Canada.

World Values Survey data also suggests that assessments of how well U.S. elections work are also often sharply split by party. That survey shows Democrats expressing concern about money in politics and women having equal opportunities to run for office, while Republicans worry about perceived problems of fair media coverage and vote buying. Pew surveys report similar partisan divisions.

So have these misgivings metastasized to infect faith in democracy itself?

As Director of the Electoral Integrity Project, established in 2012, I’ve studied these issues for many years. In a new research paper, I analyzed World Values Survey in 42 societies worldwide during the period from 2010 to 2014, and from the the U.S. in 2017.

The results suggest that perception of electoral integrity is a strong predictor of satisfaction with democracy in both the U.S. and in other nations. Feelings that elections were free and fair are more closely linked with democratic satisfaction than many other predictors, including household income and financial security, sex, race, age and education.

The only factor more strongly linked with democratic satisfaction in America was whether people had voted for Trump or Hillary Clinton. Trump voters more likely to feel positive about the outcome.

Partisan disputes over the outcome of the 2016 U.S. elections are only the latest set of problems in a system already creaking under strains. These include an excess of money in politics, the lack of gender equality and minority representation in elected office and the protection of incumbents through partisan gerrymandering.

In my opinion, the persistence of these many serious flaws combined with partisan attacks on elections and a lack of effective reforms is playing with fire and threatening faith in American democracy.

Pippa Norris does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.