Effective on Tuesday, Washington state increased the age limit for purchasing semiautomatic assault rifles from 18 to 21 years old.

For individuals between the ages of 18 and 21 years old, the law allows the individuals to possess a semiautomatic assault rifle under certain conditions. This includes in the person’s house, business, or on real property under their control. It also allows individuals to possess a semiautomatic assault rifle if they are on duty in the armed forces, hunting under a license, or practicing firearm use or target shooting at an established range.

The measure was part of Initiative Measure No. 1639, which was included on the ballot in November. It was approved by a vote of 59 percent to 41 percent. The National Rifle Association and the Second Amendment Foundation filed a lawsuit against the initiative in November.

Gun control has been an on-going debate in the US for many years. In March the Illinois House of Representatives approved three bills to tighten gun control. In November 2017 the US Supreme Court had denied review of two challenges by the National Rifle Association to state gun restrictions. In February 2017 the US Court of Appeals for the Fourth Circuit upheld Maryland’s assault weapon ban.