Texting While Driving
There’s more justification for a law against texting while driving than for helmet or seat belt requirements. A driver who doesn’t wear a seat belt is risking his own life in the case of an accident; a driver who writes text messages may endanger the lives of others.
However, if the state deems this activity too dangerous to permit, it should be illegal for everyone, not just for young drivers. We wouldn’t say that people can’t drive drunk unless they’re at least 21 years old.