Can the prosecutor object to my deferred prosecution?

Yes, but it may not matter. Most Judges will still grant the deferred prosecution. There is really no mechanism in place in the deferred prosecution law (Revised Code of Washington _ RCW 10.05) that allows for the prosecutor to object. Obviously, it may influence the Judge depending on the jurisdiction (Court), but if you are otherwise eligible (no prior deferred prosecution for DUI/Physical Control in your lifetime, alcohol/drug dependent or mental problems) it should be granted. The only times I have seen objections succeed were very unique or unusual circumstances. (i.e. person unlikely to succeed in treatment - because of much prior non-compliance or extensive history of failure to follow court orders)