Speaking today in Ohio, Donald Trump moved from questioning the integrity of primary elections to questioning the integrity of the upcoming general election, which is not the most shocking thing he's done, but perhaps one of the most dangerous. "I'm afraid the election is going to be rigged," Trump said. Forget conspiracy theories about rigged voting machines and stolen elections — what Trump just said is the real danger.

Trump has alarmed people of all political stripes for his ignorant and careless comments, so his latest throwaway remark is not surprising — but it is remarkably threatening nonetheless. US elections aren't plagued by fraud, but they are plagued by routine attempts by state and local governments to blockade minority voters from reaching the polls. And those efforts are aided by urban legends about fraud. In 2014, for example, conspiracy theories swirled on right wing sites about voting machines in Cook County, Illinois being rigged to turn Republican votes into Democratic votes. It wasn't fraud, but a glitch that affected just a handful of voters. Still, the conspiracy theory that cascaded from the glitch was lasting, and since the integrity of elections is ultimately only upheld by widespread public trust, it's plausible that real damage was done just by people who speculated about fraud.

It's absolutely true that hackers and bad actors pose a risk to elections, but it's exceptionally difficult to pull off a sleight of hand that could change an outcome on election day. It's also, therefore, extremely unlikely to happen. There are very good reasons to be concerned with the security of our democratic institutions, and the 2016 election has already been materially altered by hackers who infiltrated Democratic party systems. But suggesting the election itself is "rigged" is an altogether different monster that has no basis in reality.

No losing presidential candidate has directly questioned legitimacy of results in modern era, but that may change https://t.co/6d1lNrCDrU — Brendan Nyhan (@BrendanNyhan) August 1, 2016

Voter fraud is exceptionally rare in reality, and systemic fraud in US elections is an infectiously tempting but ultimately irrational conspiracy theory. Trump, who has casually questioned President Obama's birthplace and suggested Ted Cruz's father was involved in the JFK assassination, is no stranger to conspiracy theories. But questioning the integrity of US elections as a measure of baseless partisanship is truly reckless, even at a time when foreign hackers appear interested in interfering with the democratic process.

Democratic institutions are enabled by norms as much as they are by laws, and suggesting misconduct months before an election is abnormal. It's crazy for a presidential nominee to casually suggest an election is fraudulent before it takes place. Donald Trump's careless bullshitting could do more damage to our democracy than a glitch in a voting machine ever could.