Some good news from the front of international politics. The leaders of the U.S., Canada and Mexico have pledged at the “Three Amigo’s” summit in Ottawa that they will generate 50 percent of their power from clean energy by 2025. It is a jump from the current collective clean power levels of about 37 percent and will require the most work from the United States, which produces about 75 percent of the countries’ power. About a third of US power now comes from clean energy sources.