Most of the pressure on US voting infrastructure comes from inside the house. In the last couple of years, violent domestic threats against election officials have increased, endangering workers and driving them from the profession altogether. There have been scattered incidents at ballot drop boxes and polling places as early voting has begun. A federal judge in Arizona ordered members of a group called Clean Elections USA to stop carrying guns and wearing body armor near ballot drop boxes.

According to officials and researchers, casting a ballot will be easy for most US voters. US elections are in fact the most secure and rigorous they've ever been thanks to a number of initiatives, including efforts to phase out voting machines that don't produce a paper backup and the expanded use of post election audits. The erosion of public trust in any election system is as serious a threat to democracy as real-world interference is. The secret ballot is one of the most important voting protections in the US and is being highlighted in the upcoming elections.

Ben Adida is the executive director of VotingWorks, a nonprofit maker of open source voting equipment. There are more subtle ways that influence could affect the outcome of an election, and people who would break your knee caps or physically threaten you at the polls represent one extreme. Think about people who support a candidate, but don't like them very much. They may wonder if they really want to fight with their spouse or employer. There is only one vote.

Paper tickets were used for US voting until the 1890s. The spectacle and transparency of public voting were embedded in US democratic culture, so efforts to institute private voting using the now-familiarAustralian ballot method were controversial at first.

Two core democratic protections are provided by being able to cast your vote covertly. Privacy is the first benefit. Whether using a voting machine or filling out a scanned form, US voters cast their votes at the polls. They have to register to vote in public databases, but the votes they cast are completely disconnected from their identities. This means that even if a family member is voting with you at the same time, they shouldn't be able to tell you how you voted.

When you can't connect the vote to the person, there's a challenge, but we've largely solved that problem with audits after elections. We moved to the secret ballot because elections were held in public for most of American history. Poll places could become violent due to the fact that people were subject to violence.