Today, nine out of 10 Americans age 65 and older depend on Social Security benefits to lead a comfortable and secure retirement. Among all Americans over age 65, Social Security makes up more than half of their household income. This brief outlines the history of Social Security benefits in the public sector, describes the safe harbor rule and how it is intended to work, and then shows its limitations. As a concrete example, it then analyzes the pension formulas covering approximately 1.2 million active public school teachers in the 15 states and the District of Columbia that do not offer universal coverage for teachers. Similar to previous work, it shows that the pension formulas in those states do not protect teachers from receiving retirement benefits that are worth less than they would otherwise receive under Social Security. Those workers should be covered by Social Security immediately. The brief concludes with suggestions about how the Internal Revenue Service (IRS) could amend its rules to protect these workers and more closely align its policies with congressional intent.