Experts in election technology and security have warned for years that electronic voting systems are neither secure nor reliable enough to be depended on. In this case, Iowa Democratic Party officials compounded the problem by implementing a new app despite concerns that it was hastily built and not subject to rigorous testing (and despite offers of help from federal cybersecurity experts to aid in that testing).

The primary reason the failure didn’t prove catastrophic—and that verified results are expected later today—is the paper backups.

“Having a paper-based system not only mitigates the likelihood of foreign interference but also reduces the possibility of the integrity and the results or the accuracy of the results being incorrect,” says David Levine at the Alliance for Securing Democracy, a think tank in Washington, DC.

“Even if the error is by accident or a technical issue, a paper-based system should give voters confidence in the integrity of the results by allowing people to verify the outcome of the election.”

Nevertheless, conspiracy theories swirled online on Monday night, including unsubstantiated accusations of election rigging from Donald Trump’s campaign manager. Levine says that such activity can sow doubt in in voters’ minds about the integrity of elections and the democratic process.

“Confidence can impact whether or not people choose to vote,” he says. “Confidence can affect whether people trust the outcome of their election. A lack of confidence can be used by adversaries to exploit our democracy. Confidence is an absolutely critical thing.”

That’s all the more reason Iowa Democratic Party officials—and anyone seeking to introduce high-tech into the election process—need to make sure their products are carefully vetted before any live voting takes place.

“If the Iowa Democratic Party had had more transparency here—if there had been more information about the app, about its developer, about the process under which it was configured and tested and so forth, all of that information creates a firmer ground to give credence to what they say,” Perez says. “Transparency is absolutely critical to building public trust in an age when it is so easy to create disinformation by simply saying something in social media.”

The Iowa Democratic Party, which initially expressed confidence in the new app, did not immediately respond to a request for comment.