has suggested that judicial activism can be measured simply by examining how often the court overturns precedents and invalidates federal laws. To put it mildly, that's not an adequate measure.
Were Roe v. Wade and Miranda v. Arizona activist decisions? How about Griswold v. Connecticut? Gideon v. Wainwright? Bowers v. Hardwick? Bush v. Gore? Cases that establish or curtail rights, impose prophylactic rules, or expand or narrow constitutional principles based on the interpretation of state or local laws or policies can have an impact that is more profound than the reversal of a federal law or Supreme Court precedent.
While a court that shows little restraint when it comes to reversing its own precedents can be deemed activist, there is a significant difference between a court that chooses to clarify and reconcile its past decisions and one that targets long-standing precedents for ideological reasons. Further, it's possible for the Court to interpret or narrow a past case so as to severely restrict or even eliminate its legal significance, without technically reversing the case. Similarly a Court can choose to reach radically different outcomes in two different cases by asserting a factual distinction.
The reversal of a long-standing precedent, broadly accepted and followed as the law of the land, can also be deemed more "activist" than the reversal of an obscure or recent decision upon which few rely. Brown v. Board of Education reversed Plessy v. Ferguson, ending the notion that "separate but equal" was a constitutionally acceptable treatment of racial groups. You can argue that both fireworks and nuclear bombs are explosives, but the cumulative effect of five firecrackers isn't going to approach the impact of a single nuclear blast.
Further, a court may be activist in the manner in which it approaches lower court decisions. Although more of an issue with state courts, if a supreme court develops a pattern of identifying appellate decisions it does not like, then "depublishing them" to eliminate their presidential value or summarily vacating them without hearing, it's hard not to view the court as activist. But that type of action won't show up in Adler's proposed tally.
What if a case comes before a Court, and the Chief Justice finds that the issues as briefed and argued aren't what he had hoped - so rather than deciding the case he schedules an argument in the next term of court and orders the parties to submit new briefs, raising the issue he hoped to address. Even if the case reaches only one statute or precedent, the manner in which the Court engineers the outcome is reasonably deemed more activist than a reversal without that type of machination. What if the Court chooses to ignore its own rules, and to include in its decision a holding on an issue that was neither argued nor briefed? Is that not more activist than issuing the same decision at a later date, when the issue is properly before the court?
Part of the problem with the concept of "judicial activism" is that the term has no consensus meaning and as used often translates into little more than, "The court issued an opinion with which I disagree". But I think the strongest indicia of activism are obscured by a tally of reversals, and that activism is often better indicated by the manner and extent to which a court manipulates the process in order to create the opportunity to decide certain issues, and the extent to which the court respects the ripple effect its decision may have on society.
Let's also not lose sight of the fact that an established precedent like Plessy v. Ferguson can entrench a status quo that is unacceptable. Yes, it's reasonable to be worried that an activist court might reverse precedents that establish or protect rights you hold dear, but Brown stands as an example of where the greater harm would result from allowing the precedent to stand, and how over time a once controversial decision can be accepted as the way things should be.