Jack's description of the "living constitution" is apt, but he glosses over what is really at stake. Academics have long known that the justices are motivated by their political views, and these views appear in a relatively straightforward way in their votes. Nonetheless, there has been a sustained effort by law professors over decades to prove that Warren Court-era precedents could be justified as a matter of constitutional theory, rather than simply being the policy preferences of liberal justices. To justify these case outcomes in this way is to argue that they are not political, but that they reflect the underlying rules of the game to which everyone, left and right, is more or less committed. The legal academy still has not given up on this agenda; indeed, some of Jack's own writings fall into this camp (for example, his effort to develop a liberal style of originalism). If Heller finally destroys this decades-long literature by proving once and for all that justices don't care about constitutional theory, that won't be much comfort for the victims of avoidable gun homicides, but at least some trees will be spared.
However, Jack is right to describe the constitution, in practice, as something that is political but not the same as ordinary politics. Because justices must be approved by the president and the Senate, their views will never deviate too far from the ideological mainstream. And if a right- or left-wing justice wants to write majority opinions that will influence future justices from either party, he will have to moderate his views so as to establish precedents that others can live with. Finally, because the parties take turns in power, there is always a mix of liberal and conservative justices. In essence, the power to appoint a justice gives the president the power to extend his general ideological views for decades after he leaves office, but by the same token his power is limited by the fact that most of the justices in office during his term will have been appointed by his predecessors. The net effect is a heavily conservative (in the temporal rather than ideological sense) drag on public policy. Justices in office today reflect the partisan views of presidents in office up to thirty-three years ago.
This is our system. Does it make any sense? Jack seems to think so; I doubt it. It might smooth out policy variance over time. When presidents with ambitious agendas (left or right) come to power, they must contend with a supreme court that is likely to reject their policies or some of them. You might well be willing to give up the New Deal in order to be spared the Reagan Revolution, or vice versa. It also, in effect, enhances the degree of supermajoritarianism that already exists in our heavily supermajoritarian system. A new law has to be good enough not only to please the president and Congress, but also a supreme court whose members might have different views from those of the two political branches. It seems unlikely that this system makes much sense. In exchange for the dubious advantage of variance-reduction, it produces a heavy orientation toward maintaining the status quo, and will cause problems in particular when public opinion changes more rapidly than the average justice's term.
Jack talks as though there were no alternative to this system, and the best thing to do is to help your party win, so your party's president can appoint the next justice. Perhaps he is right. But in academia, anyway, there is an increasingly widely held view that the best solution is to encourage justices to exercise more judicial restraint. This was once the view held by many conservatives, though apparently no longer; conservatives these days seem to favor originalism. Still, if liberals jump on this bandwagon more quickly than conservatives step off it, maybe a bipartisan consensus in favor of judicial restraint will finally form. Indeed, the best recent academic work (by people like Adrian Vermeule , Jeremy Waldron , Mark Tushnet , Cass Sunstein , and Larry Kramer ) points out the thin moral, political, institutional, and historical basis for judicial supremacy, and urges the justices to abandon judicial review altogether or radically limit it. And if the justices cannot be persuaded by academic argument, maybe the sting of ridicule, so effectively administered by Dahlia among others, will do the trick.