On rereading this @Policy_Exchange paper, it’s striking how poor its reasoning is.
Take this. The issue in Miller 1 was whether the ECA 1972 permitted the Government to withdraw from Treaties that that Act incorporated into UK law. The SC said “no”. 
The conclusion from that interpretation that the Government - even if it had the support of a HoC resolution and a referendum- could not withdraw without further legislation isn’t “enforcing the SC’s view of good constitutional practice”: it’s constitutional law 101.
The real point in the case isn’t tackled at all: just an unreasoned assertion that that the SC’s interpretation of the ECA was contrary to its “logical structure”.
Then this on Miller/Cherry. In any case of political significance, the SC hands victory to one side in a political controversy. Finding in the Government’s favour would have done so. This is not a valid criticism.
And the passage fails to explain how Parliament could have resolved the issue when it had been prorogued. Or how the electorate could have resolved it (apart from taking to the streets, I suppose).
Rationality is a legal test for judicial review, and has been for decades. The problem for the Government in Miller/Cherry was that the Government could give *no* reason for the length of the prorogation. Exercise of public power for no reason has always been reviewable.
It was, in that context, entirely appropriate to note the context and consequences of the decision in a system whose main characteristic is executive accountability to Parliament.
Moreover, the “dangerous precedent” argument assumes there will be other prerogative cases where the Government is unable or unwilling to state any reasons for its decision. One hopes not: but if there are, they should be reviewed.
A positive proposal. But this paragraph is bizarre. On the one hand, it would, we are assured, be a bad mistake to politicise judicial appointments. But - in a startling piece of doublethink - we are then told the Government has a “responsibility” to ensure “sound” appointments
“Sound” does not mean “brilliant” or “highly qualified”. It means ( and can only mean in this context) “politically sound”.
These are illustrations of how poor the paper is. There’s more that is quite as bad.
