Especially those who rule against Trump—that’s a bad idea, as The Wall Street Journal‘s editors correctly note. Doing this—even were it possible just once—would destroy the necessarily independent and coequal status of our judiciary.
Impeach judges who violate their oaths of office—certainly. This would apply not only to those who engage in “severe misconduct,” but also those who rule other than on the text of our Constitution or the statute before them in a specific case. Activist judges, and Justices, who rule on the basis of their view of a living constitution or on their personal view of the needs of society or how social requirements have evolved, are among those who are violating their oaths of office, which explicitly require them to uphold and defend our Constitution. Violating an oath, of office or of any other reason or purpose, would be an especially egregious and severe misconduct.
But therein lies the rub.
There is room for honest, textual disagreement on the meaning the text—the words and especially the phrases—present in our foundational documents and the statutes subsequently enacted to give flesh to them. Proving a ruling to be based on activism rather than on honest effort at textualism is deucedly hard. Moreover, even were a proof possible in a given case, the political implications would damage the perception of judicial independence, and that would be as damaging as any actual assault on judicial independence.
Better to take the longer view and elect Presidents and Senates who will nominate and confirm judges and Justices that will rule on the basis of Constitutional and statutory texts. Those confirmed would be good for several generations of election cycles and for a couple of generations of citizens. That would provide sufficient stability in law and court rulings.