President Barack Obama on Sunday warned North Korea that its threats and provocations would only deepen its international isolation and jeopardize the resumption of U.S. food aid, and he called on the North to scrap its plans to launch a satellite next month.Squinting through binoculars from an observation post at the demilitarized zone between North and South Korea, Obama got a firsthand look at North Korea, which had briefly tantalized the United States just weeks ago by raising the possibility of ending the standoff over its nuclear program with a new leader in place, only to resume its usual defiant stance with the recent satellite announcement. “They need to understand that bad behavior will not be rewarded,” Obama said, referring to the North Koreans at a news conference with South Korea’s president, Lee Myung-bak, who is hosting a nuclear security summit meeting that will include Obama and 50 other world leaders. Lee also demanded that North Korea “repeal” the decision to ...