It depends what you think is meant by the term "effective". Courts foremost serve a truth-finding function and buffer against arbitrary authority being applied to individual people.

It's always been controversial whether a court can disparage a law of broad application or impugn the president directly. The "effectiveness" of those functions was always a little speculative.

> truth-finding function

Lower courts typically deal with questions of fact and how they intersect with questions of law; higher courts (appeals courts and Supreme Court) typically deal with questions of law (ambiguity/interpretation) exclusively. Courts as an institution don't serve a "truth-finding function" so much as a "law-ambiguity removing function".

> disparage > impugn

Everyone seems focused on whether a court has the right to, like, insult the president personally. But that's not really the important part of what they're doing. They _of course_ have the right to question whether the law allows what the president is doing -- and questioning this is not disparagement or impugning.

They are meant to be a check and balance on the legislative and executive branch, but those branches are also meant to be a check and balance against the judicial. It's not a one way street. This statement is not intended to address the root current event being discussed.