Although state constitutional conventions in the United States were once called frequently and brought about significant changes in governance, recent decades have seen little convention activity. I examine the contrast between the earlier regularity of conventions and their recent absence, but from a different perspective than is usually taken—not by explaining the recent absence but rather explaining the regularity from the 1770s through 1970s. I investigate why legislatures in prior eras agreed to call conventions and how legislators’ traditional opposition to conventions was overcome on a regular basis. After identifying the state constitutional conventions held in the US and setting aside conventions that were called to join, leave, or rejoin the Union or were instigated by institutions other than legislatures, I focus on 82 conventions called at the discretion of legislators and for reasons unrelated to joining, leaving, or rejoining the Union. I identify the issues and circumstances that were responsible for legislators’ willingness to overcome their traditional opposition to holding conventions, thereby contributing to a better understanding of both the challenges in calling conventions and the occasions when these challenges can be overcome.