I disagree with respect to causality. If selective enforcement were not possible, then it couldn't happen. Imagine a (flawed, but fair) system in which, if an executive selectively failed to prosecute anyone for violating a law, then the law is nullified, just as (approximately) in the arena of trademark. An executive bound to enforce the law would result in more citizen/legislative/lobbying effort directed toward implementing better laws and fixing those that were broken or out of date.
In practice, executive (and judicial (and in general!)) discretion is important. As an example, mandatory minimum sentencing has attracted criticism. An adaptive front-line response is a good thing, but only to a point. Leaving vague or unenforced laws on the books has the potential for both abuse and compassion (see national monuments and the Antiquities act, for a non-judicial example).
>An executive bound to enforce the law would result in more citizen/legislative/lobbying effort directed toward implementing better laws and fixing those that were broken or out of date.
Or, the executive could choose not to enforce those laws (and screw people's lives over in the process) and take the initiative to scrub them from the books by introducing bills, etc. But you're right. Politicians are not usually decent people, and it's unreasonable to expect them to not play politics with people's lives.
In practice, executive (and judicial (and in general!)) discretion is important. As an example, mandatory minimum sentencing has attracted criticism. An adaptive front-line response is a good thing, but only to a point. Leaving vague or unenforced laws on the books has the potential for both abuse and compassion (see national monuments and the Antiquities act, for a non-judicial example).