On a lot of issues these days, even Americans with considerable faith in government seem capable of recognizing limits to what public policy can achieve.
It's widely argued, for example — especially among progressives — that America would be hard-pressed ever to achieve genuine "control" of its 2,000-mile border with Mexico — to truly seal off illegal immigration with a physical barrier, or an army of frontier guards, or both.
And such an effort, it's said, would require a level of domestic militarization obnoxious to American values.
Similarly, it's widely declared — surely not least by progressives — that any Donald Trump-style plan actually to deport 11 million illegal immigrants is a fantasy.
Any serious attempt at mass deportation would take years, maybe decades, we hear — and would involve oppressive police-state tactics even more alien to American ideals of liberty, privacy and limited government.
Realism likewise dominates discussion of the war on drugs, which is widely decried as a failure (again, especially by progressives). We haven't succeeded in shutting off the drug trade or preventing drug abuse, we're told. We've only succeeded in filling our streets with rivers of gang-fued bloodshed — while overcrowding our prisons with small-time drug offenders.
And the drug-war disaster, of course, is seen simply as an echo of the lesson we should have learned from Prohibition — the great historical example that proves the utter futility of trying to enforce laws that conflict with deeply rooted cultural practices.
There's considerable truth in these dry-eyed assessments of the immigration and drug-war enforcement realities.