With the 2016 election, the chant to “build that wall” seemed to drown everything else. But interest in the Roosevelt idea is still alive on both sides of the river, even as President Trump seeks billions more for his wall. So what’s the case for an international park?

The pitched battle over Mr. Trump’s wall has focused on border security and immigration policy. These are critical issues, with lives at stake. But in the midst of this heated dispute, what if we could actually strengthen day-to-day relationships among people living on both sides of the border, without seizing any private land, and also enhance security in the process? An international park would send a strong message of cooperation and hope at a moment when the loudest words are about division and despair.

A jointly managed park would recognize the region as a single ecosystem and encourage collaboration by focusing the two nations on shared environmental and climate challenges along the border, like droughts, floods and wildfires, and invasive plants and endangered species. Joint efforts at habitat restoration and water conservation would increase river flows, discourage illegal crossings and support agriculture. And the park would increase tourism, helping struggling people on both sides of the river.

The park would be managed like its United States-Canadian counterpart, with the United States and Mexico retaining separate authority over their respective lands and park visitors carrying required documents as they cross from one side to the other. At the same time, park managers, with high-level support from both Washington and Mexico City, could collaborate on everything from search and rescue and wildlife protection to scientific research and native plant restoration.

Republicans have a strong tradition, extending back to Teddy Roosevelt, of supporting parks and international conservation. Republicans and Democrats recently came together in overwhelming numbers in Congress to approve a sweeping land conservation bill. Protecting natural areas is not an alien concept for Republicans , even these days.

On the Democratic side, Senator Tom Udall of New Mexico is a strong supporter of the idea. His father, Stewart, was instrumental in enacting the Wild and Scenic Rivers Act as head of the Interior Department in the Kennedy and Johnson administrations. That law protects 196 miles of the Rio Grande in Texas and 68 miles in New Mexico.