In her work, On Democratic Backsliding, Dr. Nancy Bermeo listed three vexing problems that indicate democratic erosion, namely:
1. Promissory coups
2. Executive aggrandizement
3. Manipulating elections strategically
This is important for two major reasons. First, Trump’s actions in response to the 2020 election fit all three problems. Second, all three issues fit in this context because of Trump’s use of misinformation.
Relevant here is one of two norms “fundamental to a functioning democracy,” as described by Levitsky and Ziblatt in How Democracies Die, mutual toleration.  If politicians do not tolerate the existence of their opposition, they can artificially inflate the costs of the opposition’s existence to their voters, resulting in a level of partisanship that cements the population’s unfair distaste for one side and willingness to accept anti-democratic behavior from the other. As the authors described, “in just about every case of democratic breakdowns we have studied, would-be authoritarians … have justified their consolidation of power by labeling their opponents as an existential threat.” 
While we might assume this type of behavior would be recognized as anti-democratic and punished by voters, research from Matthew Graham and Milan Svolik shows that when restricted to “candidate-choice scenarios with combinations of partisanship and policies we typically see in the real world,” only 3.5% of voters punish their candidate by withholding their vote. Thus, politicians face high incentives and low costs to engage in election manipulation in the form of lying about their opponents, and that’s what Donald Trump did ahead of the 2020 election.
Bermeo described strategic election manipulation as a wide variety of actions “aimed at tilting the electoral playing field in favor of incumbents.”  Trump’s actions before the 2020 election exemplify this: he utilized misinformation, claiming that the 2020 election would be fraudulent even before it happened. He made his opponents into bogeymen, members of the deep state who were existential threats because they were promoters of violence and were stealing the election, making supporting Trump the only way to save democracy. By openly lying like this, Trump was violating the norms of mutual toleration by making his opponents into existential threats so that he could reap the rewards with potential voters, all to manipulate the electoral playing field in his favor.
These threats are relevant to the next major issue, executive aggrandizement. Bermeo describes executive aggrandizement as executives weakening “checks on executive power one by one, undertaking a series of institutional changes that hamper the power of opposition forces to challenge executive preferences.”  Trump’s actions fit this description to a T.
Throughout his administration, Trump was willing to utilize misinformation for threats against political opponents, but those threats increased in the build-up to January 6. Here, Trump embraced the conspiracy theories about the 2020 election being stolen and leveraged his influence to try to bully members of Congress, and later on Vice-President Pence, into overruling a democratic election and keeping him in charge. Trump again justified this level of executive aggrandizement by spreading misinformation on the 2020 election, saying it was rigged.
Some might say that this doesn’t fit the model Bermeo describes, as Trump’s use of misinformation never led to Trump himself altering any rules. I disagree as the main point of January 6 was to get Pence to change the institutional rules to allow Trump to override an election that had no illegalities. Trump’s bad faith actions prompted this action to fit into the final problem Bermeo described.
Bermeo described a promissory coup as coups that “frame the ouster of an elected government as a defense of democratic legality,” or exactly what Trump tried to achieve.  Trump justified the January 6 attempted insurrection because his supporters fought to overturn a fraudulent election. A claim that Trump continues to this day, that he is “not the one trying to undermine American democracy—I’m the one trying to save American democracy.” Rather, for Trump, this attempted coup was “common sense,” how could you expect people to allow an election that they know was stolen to be certified?
Trump is correct here, but he also reveals his true intentions. Robert Dahl described authoritarian regimes in their dealing with opposition as following the principle that “the greater the conflict between a government and its opponents, the more costly it is for each to tolerate the other,” the same is true for supporters of the government.  By lying and saying that Biden stole the election, you increase the cost of tolerating him. For Trump’s base accepting this misinformation means you believe that by tolerating Biden, you are tolerating someone who can steal elections, as well as tolerating any number of the character-based conspiracy theories Trump promoted about Democrats. Such toleration is unacceptable, making January 6 and trying to pull off a promissory coup for Trump just common sense. The need for a promissory coup does not exist without the big lie that Trump pushed that there was already a threat to democracy; misinformation was essential to the promissory coup aspect of January 6.
While I’m sure many take issue with the idea that Trump’s responses to the 2020 election are not instances of democratic erosion, the truth is that misinformation is a global phenomenon and usually anti-democratic. Promissory coup leaders utilize it to boost their legitimacy, nationalists use it to affect voters to change institutional norms in their favor, and executives use it to distract from their anti-democratic behavior, such as in the murder of journalists. Agree with the reasoning above that Trump’s behavior surrounding the 2020 Presidential election matches Bermeo’s problems involving democratic erosion, thanks to misinformation, or don’t; it’s impossible to deny that misinformation is a valuable weapon in authoritarian leaders’ arsenals and can be a major threat to democracy.
References: Nancy Bermeo, “On Democratic Backsliding” Journal of Democracy 27, No. 1 (January 2016): 8 Nancy Bermeo, “On Democratic Backsliding” Journal of Democracy 27, No. 1 (January 2016): 10 Nancy Bermeo, “On Democratic Backsliding” Journal of Democracy 27, No. 1 (January 2016): 13 Steven Levitsky and Daniel Ziblatt, How Democracies Die, (New York: Broadway Books), 2018. 102 Steven Levitsky and Daniel Ziblatt, How Democracies Die, (New York: Broadway Books), 2018. 106 Nancy Bermeo, “On Democratic Backsliding” Journal of Democracy 27, No. 1 (January 2016): 13 Nancy Bermeo, “On Democratic Backsliding” Journal of Democracy 27, No. 1 (January 2016): 10 Nancy Bermeo, “On Democratic Backsliding” Journal of Democracy 27, No. 1 (January 2016): 8 Robert Dahl, Polyarchy: Participation and Opposition, (New Haven: Yale University Press), 1971, 15.