Whether in medical issues or other issues, politicians don't even have to prove that what they advocate is possible, much less probable.
For example, those who advocate tighter gun control laws are almost never asked for evidence that such laws have in fact reduced gun violence. And almost never do they even attempt to present such evidence.
But the only way that it is possible that such laws will save lives is if they do in fact reduce killings with guns.
But who cares what is possible these days? If the intention is good and the means sound plausible, who wants to get bogged down in specifics?
Certainly not politicians or most of the media. All you really need is rhetoric that puts you on the side of the angels against the forces of evil.
On the international stage, the ever-popular policy of "disarmament" is in essence domestic gun control writ large. Nuclear disarmament is especially popular.
No doubt many people wish that scientists had never discovered how to make such devastating weapons.
But once the principles on which nuclear bombs operate have been discovered, it is impossible to undiscover them.
Even if you destroyed every nuclear bomb in the world, the knowledge of how to make them cannot be destroyed. If you killed every scientist who has this knowledge, such a bloodbath would be futile, because new scientists can discover what the old scientists discovered.
With international disarmament agreements, as with domestic gun control, nothing is easier than disarming peaceful people - thereby leaving them more vulnerable to people who are not peaceful, who can simply ignore the restrictions that others obey.
But if verifiable, lasting and universal nuclear disarmament is impossible, who cares, so long as it sounds good?
Politics is the art of the impossible.
Sowell is a senior fellow at the Hoover Institution at Stanford University in California. His website is www.tsowell.com.