When the world’s largest conference on sustainability and green construction comes to Washington, D.C. on the cusp of a presidential race and titles its opening plenary “What Will It Take to Get Meaningful Action on Climate Change?” you might expect an “us vs. them” attitude and perhaps a little Republican-bashing. But although Greenbuild 2015’s kickoff event was politically minded, the tone was anything but rancorous.

U.S. Department of Housing and Urban Development secretary Julián Castro, his tie a bipartisan shade of purple, opened with a talk on how sustainability benefits everyone, from governments to businesses to the man on the street. “Green building is not a slogan,” he said, “but a solution”: for healthier homes and environments, for greater resilience to increasingly severe weather, and for economic growth. Apart from briefly mentioning the Obama administration’s green bona fides, the closest Castro came to campaign rhetoric was his observation that by creating more sustainable buildings and communities, “we are ultimately building a stronger America.”