WASHINGTON — President Obama is exploring alternatives to a major troop increase in Afghanistan, including a plan advocated by Vice President Joseph R. Biden Jr. to scale back American forces and focus more on rooting out Al Qaeda there and in Pakistan, officials said Tuesday. Vice President Joseph R. Biden Jr., who spoke Tuesday in National Harbor, Md., wants to scale back troops in Afghanistan. The options under review are part of what administration officials described as a wholesale reconsideration of a strategy the president announced with fanfare just six months ago. Two new intelligence reports are being conducted to...