An expansion of our recent analysis of Stand Your Ground laws confirms that an additional five states, and perhaps more, have passed legal language strikingly similar to the Florida law that has gained national attention in the wake of Trayvon Martin’s death. In addition to the previously identified states, Alabama, Georgia, North Carolina, Utah, and Illinois passed laws that appear to share substantial overlap with the legislation enacted in Florida.

Sunlight’s initial analysis demonstrated that at least ten states had passed bills sharing substantial overlapping text with the Florida measure. However, our report was limited by the availability of legislative text, and we intentionally confined its scope to the text of bills that were enacted after the Florida law’s passage in 2005.

With research assistance from the Legal Community Against Violence, we expanded our analysis to include a wider collection of state-level self-defense laws, as well as statutory text in cases where original legislative language could not be obtained. As a result, we can now confirm that measures on the books in at least 15 states share meaningful amounts of overlapping language with the Florida law — one such example is the phrase “a person does not have a duty to retreat” — implying connections related to these laws’ provenance and spread. This analytic finding is consistent with reports that the Florida law was adopted and promoted to other states by the American Legislative Exchange Council and the National Rifle Association.

Our analysis also hints at some of the origins of the Florida law. Illinois and Utah’s measures represent earlier “Castle Doctrines.” But these bills lacked some of the provisions of the Florida measure that are considered to be most problematic, such as the presumption of innocence for those using deadly force. And it was the Florida bill that appears to have been used as a template by most states that have since adopted “Stand Your Ground” laws.

Although our expanded analysis examined legislative or statutory language from 45 states, in some cases data availability remains a limiting factor. In others, laws may be substantially similar or share a common origin but lack overlapping language. Our analysis is limited to overlapping, identical text (we ignored matching text that appeared to be a product of short or frequently-used legal boilerplate). It is important to note that the 15 matches we located represent a lower bound; the total number of states that have adopted bills inspired by Florida’s may well be higher.

Sunlight’s work relies on software called SuperFastMatch. Created by the Media Standards Trust and supported by a grant from Sunlight, SFM allows for the identification of overlap between text documents at large scales and high speeds. You can examine the connections between the “Stand Your Ground” measures we have collected for yourself by visiting our research instance of SFM. Click the “Documents” tab to begin exploring the different self-defense-related measures we examined and their degree of overlap with those of other states.