Peter Bergen wrote for CNN about President Trump's plan for Afghanistan:
The elements of President Donald Trump's approach to the Afghanistan war are emerging -- and they're markedly different from the stance President Barack Obama took. For one thing, Trump is committing US military forces to a long-term and open-ended deployment in Afghanistan, according to a senior US official.
Obama surged tens of thousands of additional US troops into Afghanistan, but when he gave a speech at West Point on December 1, 2009, announcing the new troops, he also simultaneously announced their withdrawal date.
For the Taliban, the Afghan government and Afghanistan's neighbors such as Pakistan, the headline of Obama's West Point speech was not the surge of new troops, but the withdrawal date. This had the counterproductive effect of encouraging the Taliban to wait out the Americans.
It also undermined confidence among Afghans and it affected the hedging strategy of Pakistan's military intelligence service, ISI, which has long supported elements of the Taliban.