Stanley mcchrystal

WASHINGTON - The president of the United States and the president of Russia enjoyed quite a summer's day on Thursday: Grab some burgers, joke about Twitter, take a walk in the park.

HALIFAX, Nova Scotia - British Prime Minister David Cameron steps into a potential hornets' nest of trans-Atlantic conflict when he makes his global debut this week at the G-20 summit in Canada - with tensions over Afghanistan, Europe's debt crisis and the BP oil spill gaining in intensity.