Plunging headlong into the issues of the day, Pope Francis opened his visit to the United States with a strong call Wednesday for action to combat climate change, calling it a problem that "can no longer be left to a future generation." President Barack Obama, in turn, hailed the pontiff as a moral force who is "shaking us out of our complacency" with reminders to care for the poor and the planet. The White House mustered all the pageantry it had…