What does John 11:53 mean?

This is the ultimate verdict of the council which gathered to discuss Jesus' latest miracle: the raising of Lazarus (John 11:39–44). This decision corresponds with Scripture, countering the claim that non-believers only need more evidence (Romans 1:18–20; Luke 16:31). Many of these same men were accused of "refusing" to accept the truth (John 5:39–41). Now, in response to a blatant miracle, they respond with deeper commitment to wipe that evidence away! In fact, their desperation will even extend to seeking death for the man Jesus brought back (John 12:9–11).

Prior to this, Jesus' critics have made efforts to arrest or even kill Him (John 7:44–46; 10:39). The moment described here is notable because it's an official ruling. Prior attempts have been half-hearted or arranged by a few angry leaders. This death sentence, as stated here, is now the goal of the entire religious leadership of Jerusalem. Among them are dissenters, either too afraid (John 19:38) or lacking influence to intervene (John 7:50–52). In an official sense, though, this means Jesus' fate has been sealed. The Council is only interested now in finding a way to capture Jesus away from crowds (Mark 12:12; Matthew 21:46). The "trials" He will experience after His arrest are shams: the sentence of death has been pronounced, here, long before He's even arrested.