Immediate Consequences:
* No Death Eaters attack: Cedric Diggory would still be alive. The Death Eaters wouldn't have been able to use the Triwizard Tournament as an opportunity to infiltrate Hogwarts and get Voldemort back into a body.
* No resurrection of Voldemort: Without Harry being in the tournament, Voldemort would not have been able to use Harry's blood to resurrect himself.
* Less conflict with the Ministry: The Ministry of Magic would not have been forced to acknowledge Voldemort's return so early, potentially delaying the war and giving Dumbledore and the Order more time to prepare.
* No Order of the Phoenix: Dumbledore might not have felt the need to re-establish the Order as urgently, as the threat of Voldemort's return would have been less immediate.
* No Ministry takeover: Without the Death Eaters' attack, the Ministry wouldn't have been infiltrated and taken over by Voldemort's supporters.
Longer Term Consequences:
* Voldemort's power grows: While delayed, Voldemort would still eventually have been able to return, perhaps through other means. The Ministry's denial of his return would make him even more powerful and dangerous in the long run.
* Less awareness of the threat: Without a public, visible resurgence of Voldemort, the wizarding world might have been less prepared and more complacent about the threat of his eventual return.
* Less unity among the forces of good: The Order of the Phoenix may have been less unified without the immediate threat of Voldemort, potentially leading to internal conflicts or disagreements.
* Dumbledore's plans: Dumbledore's plans for Harry might have been different. He may have tried to keep Harry out of the limelight, perhaps even taking him away from Hogwarts, to protect him from Voldemort.
* Harry's personal development: Harry's experience in the Triwizard Tournament was crucial to his development as a wizard and a person. Without it, he may have been less prepared for the challenges that lay ahead.
Overall: While avoiding the Triwizard Tournament might have delayed Voldemort's return, it wouldn't have necessarily prevented it. The long-term consequences could have been even more devastating, leaving the wizarding world more divided, less prepared, and potentially more vulnerable to Voldemort's eventual rise to power.