Analysis: Obama presidency at pivotal moment

NEW YORK – When President Barack Obama said the United Nations had reached "a pivotal moment," he could just as well have been referring to his own presidency.

Both on the world stage and at home, Obama keeps asking for more, politely but firmly. But he's still had no signature win, not the kind that would set off a chain reaction of other victories.

For the U.N., Obama is seeking global cooperation to confront the challenges of bloody conflicts, a warming planet, economic deprivation and dangerous weapons proliferation. For his presidency, he's seeking the kind of high-fiving, powerful victory that a major health care overhaul would represent.

Power begets power, and success begets success, and no one knows this better than Obama's chief of staff, Rahm Emanuel. "In politics, power is not static," he said in an interview Wednesday with PBS' Charlie Rose. "As you use it, if you're successful, it accumulates to achieve other goals."

Easier said than done, though Thursday's Security Council approval of a resolution embracing Obama's goal of a world free of nuclear weapons was a plus. So was the three-way Mideast leaders' meeting he engineered and led....