The right to shelter was born of moral urgency in the 1980s. With thousands of New Yorkers sleeping on the streets, it was the most humane and effective remedy. But I’ve seen its limits. In the early 1990s, I joined social workers reaching out to people in the squalor of the Amtrak tunnels under Riverside Park. Later, I responded to complaints from shelter residents and rode with teams coaxing people out of remote encampments.