Americans — despite electing the candidate who promised to “drain the swamp” in 2016 — are angrier now than they were before that landmark election, and that spells trouble for both incumbent President Donald TrumpDonald John TrumpWHCA calls on Trump to denounce video depicting him shooting media outlets Video of fake Trump shooting members of media shown at his Miami resort: report Trump hits Fox News's Chris Wallace over Ukraine coverage MORE and Democratic front-runner Joe BidenJoe BidenTrump hits Fox News's Chris Wallace over Ukraine coverage Schiff: Whistleblower testimony might not be necessary Trump warns Democrats will lose House seats over impeachment MORE.

An August NBC News–Wall Street Journal poll reported that 70 percent of Americans felt angry about the current political system. This percentage was a slight increase over that of the October 2015 poll results. In both cases, a majority of respondents felt that politicians favored political elites, rather than everyday Americans.

Two-thirds of those responding to the 2019 survey also felt that their children’s generation would be worse off than their own.

These results are problematic for both Trump and Biden’s presidential chances in 2020. Trump, who rode a wave of anger to the Republican nomination and the White House in 2016, appears to be using the same campaign playbook in 2020. This strategy, however, may backfire on him, making him a one-term president.

Biden, running as a moderate and one who wants to restore normalcy to politics — a return to pre-Trump times — may also find that the electorate does not share his nostalgia for the pre-2016 political world.

During the last two decades, voters have shown little patience for political results and little hesitancy in voting political parties out of power.

Since 2000, the electorate has desired change and almost each election cycle has demonstrated that anger and dissatisfaction produce discontinuity in political power. The 2000 presidential election resulted in George W. Bush beating Vice President Al GoreAlbert (Al) Arnold Gore2020 general election debates announced Odds place Greta Thunberg as front-runner for this year's Nobel Peace Prize Joe Lieberman's son running for Senate in Georgia MORE, who should have benefited from the high approval ratings of Bill ClintonWilliam (Bill) Jefferson ClintonA Republican Watergate veteran's perspective on a Trump impeachment Beware the 34th month of Trump's presidency How to survive an impeachment MORE, but the electorate — and Supreme Court — wanted change.

Change continued during the Bush administration as Democrats won back both houses of Congress, as Republicans paid the price for the public’s anger over long wars in Afghanistan and Iraq.

Barack ObamaBarack Hussein ObamaEach of us has a role in preventing veteran suicide Why calls for impeachment have become commonplace Meet Trump's most trusted pollsters MORE benefitted from the public’s desire for change away from Bush policies and anger over a growing recession. Yet the optimism over Obama’s election quickly turned to anger as Republicans, stoked by Tea Party rhetoric, took majorities in the House and Senate by 2014.

Even Trump has felt the winds of change as the 2018 midterms caused Republicans to lose control of the U.S. House of Representatives. The October 2015 results of the NBC–Wall Street Journal poll showing that 69 percent of Americans felt anger toward Washington was great news for Trump’s insurgent presidential campaign. An even higher number in 2019, however, is a sign that Americans are losing patience with Trump’s excuses and performance.

Also, Biden’s lead in tracking polls heading into the fall may be false hope to his campaign. Polls suggest that over two-thirds of Democratic primary voters are not solid in their preference for their nominee. As the reality of the primary campaign develops, candidates like Elizabeth WarrenElizabeth Ann WarrenSanders can gain ground by zeroing in on corruption Biden praises Buttigieg for criticizing GOP attacks: 'That's a good man' Warren enters crucial debate with big momentum MORE and Bernie SandersBernie SandersSanders wishes Ocasio-Cortez happy birthday Video of fake Trump shooting members of media shown at his Miami resort: report Sanders can gain ground by zeroing in on corruption MORE are much better equipped to appeal to the Democratic electorate’s desire for change.

We should expect to see volatility in American politics well into the future. Anger and dissatisfaction are difficult to change, even during a period of high employment. There are different fundamentals driving these feelings — cultural and demographic changes affecting the country, record income and wealth gaps, and a polarized media environment stoking hyperpartisanship.

Come election day 2020, voters will likely opt for the candidate that promises the biggest, most sweeping changes, the candidate who’s most outside the establishment — just as they did in 2016. Neither Biden nor Trump seems to be heading in that direction.

David McLennan is a professor of political science at Meredith College in Raleigh, N.C., where he also directs the Meredith Poll.