D.C. residents to vote on the initiative but preventing the results from being made public. The amendment was challenged by the American Civil Liberties Union on grounds that it violated First Amendment rights, and in September 1999 U.S. District Judge Richard W. Roberts agreed, overturning the Barr amendment. Rep. Barr then introduced a similar amendment which became law in November 1999, setting off a long legal battle until finally in December 2009 the Barr amendment was removed from the annual D.C. appropriations bill, allowing the original 1998 ballot initiative to move forward. Following the approval of several ballot measures in 1998, Maine voters passed a medical cannabis initiative in 1999 that was expanded by both state legislature and another ballot initiative in subsequent years. In 2000, medical cannabis initiatives were passed in the states of Colorado and Nevada, with Nevada's initiative passing for a second consecutive election as required to amend the state's constitution. Also in 2000, Hawaii became the first state to legalize medical cannabis through an act of state legislature. In the following years, medical cannabis was legalized by ballot measure in Montana (2004), Michigan (2008), Arizona (2010), Massachusetts (2012), Arkansas (2016), Florida (2016), North Dakota (2016), Oklahoma (2018), Missouri (2018), Utah (2018), and South Dakota (2020), and by an act of state legislature in Vermont (2004), Rhode Island (2006), New Mexico (2007), New Jersey (2010), Delaware (2011), Connecticut (2012), New Hampshire (2013), Illinois (2013), Maryland (2014), Minnesota (2014), New York (2014), Pennsylvania (2016), Louisiana (2016), Ohio (2016), West Virginia (2017), Virginia (2020), Alabama (2021), and Mississippi (2022). Eighteen states have legalized by ballot measure and 19 have by state legislature, for a total of 37 states according to the National Conference of State Legislatures. The U.S. territories of Guam (2014 – ballot measure), Puerto Rico (2015 – executive order), the Northern Mariana Islands (2018 – legislature), and the U.S. Virgin Islands (2019 – legislature) have also legalized the medical use of cannabis. Low-THC, high-CBD laws In addition to states that have passed comprehensive medical cannabis laws, a number of states have passed more restrictive laws that limit the allowable concentration of tetrahydrocannabinol (THC), the main psychoactive component of cannabis. The primary purpose of these laws is to allow for the use of cannabidiol (CBD), a non-psychoactive cannabinoid that has been shown to be effective in the treatment of seizure disorders, particularly in children. The use of CBD