In Jan­u­ary, five cli­mate jus­tice activists charged with crim­i­nal tres­pass­ing in Wash­ing­ton state pre­sent­ed a nov­el defense. Their deci­sion to block the pas­sage of a train in the BNSF Delta rail yard in Sep­tem­ber 2014 was nec­es­sary, they argued, because of the cat­a­stroph­ic threat of cli­mate change.

The testimony given was the “most comprehensive case for climate action … that I’ve ever seen in an American courtroom.”

The so-called bomb train was car­ry­ing Bakken crude, an espe­cial­ly dirty type of oil. Since 2013, there have been at least two dozen fires and explo­sions aboard trains car­ry­ing the crude, which is high­ly flammable.

The tri­al of Mike LaPointe, Patrick Maz­za, Jack­ie Minchew, Liz Spo­er­ri and Abby Brock­way — known as the Delta 5— was the first time this ​“cli­mate neces­si­ty defense” has been pre­sent­ed before a jury in a U.S. court­room. A neces­si­ty defense is used when a defen­dant claims there was no choice but to break the law — by tres­pass­ing in order to escape phys­i­cal harm, for example.

Anti-nuclear activists have pre­vi­ous­ly used this defense to argue the harm they’re protest­ing is greater than any harm caused by civ­il dis­obe­di­ence. In 2011, activist Tim DeChristo­pher attempt­ed to use a cli­mate neces­si­ty defense against two felony charges, which he received after sab­o­tag­ing a fed­er­al auc­tion to stop pub­lic lands in Utah from being sold to gas and ener­gy com­pa­nies. The judge did not allow this defense, and he was sen­tenced to two years in prison.

The Delta 5, how­ev­er, were per­mit­ted to argue that the threat of cli­mate change requires direct action. In a four-day tri­al, they drew tes­ti­mo­ny from cli­mate sci­en­tists, pol­i­cy experts and doc­tors. The pro­test­ers won praise from Sno­homish Coun­ty Judge Antho­ny Howard, who called them ​“tire­less advo­cates of the kind we need more of in this coun­try.” Ulti­mate­ly, how­ev­er, the judge decid­ed that the tes­ti­mo­ny hadn’t met one of the four cri­te­ria for a neces­si­ty defense — that there was no rea­son­able legal alter­na­tive to the defendant’s actions. A jury found the group guilty of tres­pass­ing and acquit­ted them on a sec­ond count of train obstruc­tion. While the pro­test­ers received pro­ba­tion and fines, they avoid­ed jail time. The case also set an impor­tant moral and legal prece­dent for fur­ther actions. The tes­ti­mo­ny giv­en was the ​“most com­pre­hen­sive case for cli­mate action … that I’ve ever seen in an Amer­i­can court­room,” DeChristo­pher said in an inter­view with Democ­ra­cy Now! ​“It’s a tremen­dous resource for future activists tak­ing their case to court.”