A man jailed for failing to register as a convicted sex offender has been given the go-ahead to pursue a lawsuit alleging that the city of Chicago is responsible for his incarceration. In a written opinion, U.S. District Judge Matthew F. Kennelly did not rule on the merits of John Saiger’s claim that the city has a policy of refusing to register homeless sex offenders and that this purported policy violated his right to due process. But Kennelly held that Saiger “has stated a facially viable procedural …