How can parents bring up the topic of drug testing without risking damage to their parent/child relationship and trust?

In some families, you can damage relationships by simply voting Republican… or Democrat, by rooting for the Cubs… or Yankees. The “silent treatment” can go on for years. Jeez… some people are sooooo touchy. We encourage parents to talk to their kids, explain their concerns, establish rules and communicate the means by which the rules will be enforced (i.e. testing). It simply establishes the means by which trust is earned and maintained. It should go without saying that any "damage" to a parent/child relationship brought on by merely discussing substance abuse testing programs, would be by comparison, a tiny fraction of the damage and destruction likely to be caused by actual substance abuse.