As the midterm elections draw near, employees might need a reminder that the First Amendment does not apply to political speech in the workplace.

"The First Amendment protects people only from government interference with speech, not employer interference," said Matt Simpson, a partner at national labor and employment firm Fisher Phillips.

A CareerBuilder survey from 2012 showed 23 percent of workers who have discussed politics at work reported they had a heated discussion or fight with a co-worker, boss or someone else higher up in the organization.

The survey also found 10 percent of workers said their opinion about a co-worker changed after they discovered that person's political affiliation, with most stating it changed for the negative.

The Society for Human Resource Management reports about 25 percent of employers have written policies proscribing political activities such as party organizing, soliciting campaign donations, posting political signs or holding rallies in common areas.

"In most states, private employers can prohibit the discussion of politics at work," Simpson added. "They are within their rights to discipline or even fire an employee for engaging in this activity. They can also ban the use of company technology to access political websites or to make statements on social media."

Workplace anti-harassment rules should always be kept in mind, according to Simpson.

"A candidate’s race, religion, gender, age or any other 'protected status' may cause issues," he explained.