From Dominion to optical scanners: What you need to know about voting machines

As elections in the United States evolve with technological advances, so does the voting process itself. Voting machines offer citizens different ways to cast their ballots, while helping officials manage and count votes more efficiently. From optical scanners to digital interfaces, these machines streamline election operations and, when combined with robust security measures, help maintain the integrity of elections. However, the public still has questions about the operation and security of the devices, criticized in large part by Republican candidate Donald Trump, who since his 2016 campaign has spread false information and conspiracy theories claiming that such devices were hacked or altered to eliminate votes. In fact, in 2020 he and several of his allies pushed the theory that Dominion Voting Systems had given millions of votes to his opponent, Joe Biden, leading the company to file defamation lawsuits, including one against Fox News that was settled out of court with a $787.5 million payout.

Here’s a deep dive on these machines:

Types of Voting Machines

In U.S. elections, several types of voting machines capture and tabulate votes, each with unique features tailored to different needs. Among the most commonly used are optical scanners, direct recording electronic (DRE) systems, ballot marking devices (BMDs), and hybrid voting systems.

Optical scanners are common in jurisdictions that use paper ballots. Voters fill out a paper ballot, usually by marking the spaces designated for each selection. Once completed, the ballot is fed into a scanner, which reads and records each vote. These machines are divided into two categories: precinct scanners and central scanners. The former are located at the polling stations and scan each ballot in situ as the voter casts it. Central scanners, on the other hand, process groups of ballots at a centralized location, usually reserved for mail-in ballots.

Direct Registration Electronic (DRE) systems are fully electronic machines that allow voters to select candidates and issues on a screen using a touch screen or dial. Once the voter makes his or her selection, the DRE digitally records the vote in its memory. To increase voter confidence and facilitate auditing, many DREs also print a Voter Verified Paper Audit Trail (VVPAT) along with the electronic record. This paper serves as a backup in case of discrepancies and is securely stored for audits or recounts.

Ballot Marking Devices (BMDs) are designed with a focus on accessibility and provide an electronic interface where voters can make their selections. Once the choice is made, the BMD prints a ballot, which the voter can review before submitting it. Unlike DREs, BMDs do not store the votes directly, but instead produce a readable ballot that is scanned at the polling station or collected for counting at a central location.

Hybrid voting systems combine features of BMDs and optical scanners, allowing voters to mark their selections and immediately scan their ballots within a single machine. This configuration simplifies the process, allowing for direct and immediate tabulation, while providing a physical record of each vote.

Election security

Voting machines are rigorously tested, secured and monitored throughout the election process to prevent tampering or malfunction.

One of the main safeguards for voting machine security is the creation of a paper trail. In recent years, states have prioritized a return to paper records, as these physical copies allow election officials to audit results if discrepancies arise. About 98% of votes cast in the 2024 election, for example, will have a paper record. Audits can help compare electronic results with physical records, which increases confidence in the accuracy of machine counts.

Beyond paper records, the machines undergo strict testing protocols. Before deploying any of these devices, election officials conduct preliminary tests to ensure that they are functioning properly. These are repeated after the election to confirm the accuracy of the operation. In addition, the machines are programmed with cybersecurity measures, including encryption and access controls, to protect data integrity. Election jurisdictions typically store voting machines in secure, guarded locations and limit physical access to authorized personnel only.

Despite the robust security surrounding voting machines, concerns persist about vulnerabilities in voting systems. Election security experts make it clear that any technology can have weaknesses. Regular software updates, audits and constant review of voting machine security are essential to keep protection against potential interference up to date.

Misinformation about voting machines

In recent years, misinformation about voting machines has become a focal point in election security debates, especially regarding claims that the machines “change” votes. In October 2024, false claims circulated on social media alleging that voting machines in Tarrant County, Texas, changed voter selections. Election officials investigated and confirmed that no tampering or machine error had occurred, and attributed the problem to human error.

This type of misinformation is not new; there have been reports of vote-switching in previous election cycles. Officials stress that the reported incidents are usually due to voter error, when a person may select the wrong option on a touch screen, similar to what happens with a telephone keypad. Election officials advise voters to carefully review their ballots before submitting them and assure that each ballot can be corrected if errors are detected before it is cast.

Election officials in Georgia and Tennessee also addressed similar claims. They provided explanations and debunked viral stories. In Georgia, a rumor circulated suggesting that Dominion Voting Systems equipment changed votes. However, state and local officials clarified that the incident was again due to user error, not a machine malfunction.

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