The problem is when the law is vague regarding a particular issue. Look at Massachusetts v. EPA (2007).
The Clean Air Act (CAA) of 1963 requires the EPA to set emission standards for "any air pollutant" from motor vehicles or motor vehicle engines "which in his judgment cause[s], or contribute[s] to, air pollution which may reasonably be anticipated to endanger public health or welfare."
The main question of that case was whether CO2 and other greenhouse gases are an "air pollutant" that causes "air pollution". Unsurprisingly, the CAA didn't specify each and every "air pollutant", rather Congress implicitly left it to the EPA.
So the problem was not whether Congress had explicitly delegated regulation to an administrative agency but whether the EPA was required by statute to regulate CO2 and other greenhouse gases.
Going forward, deference to the administrative agency is not required. The judiciary can certainly still side with an administrative agency. However, the courts will have to play a larger role in addressing technical statutory questions. The courts have always been able to disregard agency expertise (as SCOTUS just did), this just signals a greater willingness to do so.
The Clean Air Act (CAA) of 1963 requires the EPA to set emission standards for "any air pollutant" from motor vehicles or motor vehicle engines "which in his judgment cause[s], or contribute[s] to, air pollution which may reasonably be anticipated to endanger public health or welfare."
The main question of that case was whether CO2 and other greenhouse gases are an "air pollutant" that causes "air pollution". Unsurprisingly, the CAA didn't specify each and every "air pollutant", rather Congress implicitly left it to the EPA.
So the problem was not whether Congress had explicitly delegated regulation to an administrative agency but whether the EPA was required by statute to regulate CO2 and other greenhouse gases.
Going forward, deference to the administrative agency is not required. The judiciary can certainly still side with an administrative agency. However, the courts will have to play a larger role in addressing technical statutory questions. The courts have always been able to disregard agency expertise (as SCOTUS just did), this just signals a greater willingness to do so.