But the president was hardly speaking about a place of domestic political strength: Although Mr. Trump carried Pennsylvania last fall, 75 percent of voters in Pittsburgh voted for Hillary Clinton.
In defiance of the president, city leaders vowed again on Thursday to pursue their own climate action. Pittsburgh, they point out, is the wrong metaphor anyway: The former steel hub has spent the last 30 years trying to remake its economy in precisely the mold that climate advocates envision.
Once among the most polluted cities in the country, Pittsburgh today is increasingly rebuilding around greener medical complexes, research universities and tech offices. In place of steel mills, the city now has its own Google outpost and test track for autonomous cars. The U.S. Steel Tower, the tallest building in town, now bears the name of the University of Pittsburgh Medical Center. The local renewable energy industry employs 13,000 people, according to the city.
