text: admin law question for law students-lawyers-attorneys-judges? under chevron, you can't review an agency action if the legislature left the decision to the discretion of the agency.  but we have these six grounds for overturning agency action, like when they don't follow procedure or acted unlawfully.  how can you ever challenge and overturn on those six grounds if you can't even challenge the action? i am not sure where did you get an idea that you cannot challenge the action under chevron.  chevron approach – to resolving by court if the construction is legal is roughly this: 1. ask: did congress directly speak to the issue? if the congress has answered – keep the agencies to that. 2.if congress did not speak:       a. check if the agency has reasonably resolved the precise issue? if the agency's interpretation is unreasonable, or impermissible -- based on other congressional intent or on constitution -- remand it back to the agency so that the agency can change it.       b. if the congress has explicitly delegated the policy to the agency,  the agency is allowed any policy as long as it reasonably serves the purpose of the statute, but it can still be stricken down if it is  arbitrary, capricious, or contrary to the statute.  so nowhere i the chevron does it say that you can't challenge agency action