defecting

dɪˈfɛkt

verb

abandon one’s country or cause in favour of an opposing one.

he defected to the Soviet Union after the war

desert,go over to the enemy,turn traitor,rebel,renege,abscond,go AWOL,quit,escape,shift ground,break faith,be apostate,apostatize,abandon,renounce,repudiate,secede from,revolt against,rat on,forsake,tergiversate