JERUSALEM — Last year, when the Trump administration was still trying to entice the Palestinians into peace talks with Israel through cooperation rather than coercion, it encouraged the two sides to team up on small-scale infrastructure projects as a way to rebuild trust while improving conditions in the here-and-now.

Deep in the Negev Desert, a group of Israeli and Palestinian civilians did just that. They hammered out creative ways to bring solar power, sewage treatment and clean water to the impoverished Gaza Strip, where the lights are out more than they are on, the aquifers are befouled, and raw sewage has been pouring into the Mediterranean — sometimes overwhelming a nearby Israeli desalination plant with pollution.

Their plans were aimed at creating jobs, improving public health and, above all, sustaining hope in a place where that is in short supply. But in the time it took them to see to the nuts and bolts — business plans, site selection, Israeli military approvals, and the hiring of engineers and workers in Gaza — the political context changed radically.

The Trump administration recognized Jerusalem as Israel’s capital. Angry Palestinians began regularly denouncing the White House, and the administration’s approach to them became no-carrot, all-stick.