Here’s why it matters that the Speaker of the U.S. House and a major congressional delegation went to the United Nations climate summit last week.

Other nations’ leaders are capable of looking ahead, and right now they have to be wondering whether there’s a future for global cooperation on climate change that includes the United States. They couldn’t have asked for a stronger signal of “yes” than Speaker Nancy Pelosi’s attendance.

Everyone knows the future of United States climate policy — will we or won’t we once again acknowledge the urgency of acting? — depends in large part on the 2020 election outcome. Now the world has been forcefully told if President Trump is defeated, the new party in power is institutionally committed to progress.