Meghan O'Sullivan, a former member of the Bush National Security Council from 2004 to 2007, and deputy national security adviser for Iraq and Afghanistan, has penned an op-ed in Bloomberg that points out that Trump's removal of Obama's timeline from the Afghanistan strategy was not without risks but the right thing to do.

Nothing did more to undercut Obama's 2009 surge of troops into Afghanistan than his announcing in advance when Western forces would be pulled out. Given that no victory over the Taliban was conceivable, the only realistic objective of more military might was to bring the enemy to the negotiating table. Yet as long as waiting out U.S. resolve was a distinct option, compromise never seemed attractive to the Taliban, and the war dragged on. This is not just my opinion. It is also that of the U.S. ambassador to Afghanistan under Obama, James Cunningham, who said as much to an audience at the Aspen Institute just last month.

Ditching the timeline will also help strengthen the nation's institutions critical to success. Afghans were reluctant to invest in a state when the chances of its failure seemed high; instead, many in important roles saw their time in government as little more than a chance to position themselves as well as possible for when the state collapsed. But now that the U.S. seems committed to staying, Afghans are more likely to see the state as worthy of their efforts to create a new reality.

Finally, losing the timeline could make a big impression on two countries that are not mentioned in Trump's speech, but are creating major obstacles to a better Afghan future: Iran and Russia. Both governments have upped their meddling, likely positioning themselves for what was perceived as an imminent American departure.

For all these reasons, removing an arbitrary timeline from the U.S. Afghan strategy will make it a significantly different approach than that tried under Obama – with better prospects for success.

For nearly 16 years, Democrats have been demanding a date certain for withdrawal from Afghanistan – just as they did in Vietnam, Panama, and Iraq.  In what fantasy universe is this sound policy?  Even the village idiot could figure out that telling the enemy when you are leaving encourages him to lie low until our forces are too weak to resist.

The absence of U.S. troops in Iraq encouraged ISIS to attack.  The drawdown of U.S. troops in Afghanistan has emboldened the Taliban.  Now Trump is altering that equation and putting doubts in the mind of the enemy.  This is a very good thing, and it makes criticism of Trump's plan that it's too much like Obama's policy ring hollow.

There are other differences between Trump's strategy and Obama's, perhaps most importantly the change in attitude toward Pakistan and calling on India to do more to assist our efforts.  As I write this, the entire Taliban leadership is meeting in Quetta, Pakistan.  These men are plotting the deaths of American servicemen, and the Pakistani government is looking the other way.  Trump was absolutely right to call out Pakistan for its support of our enemies and doubly right to threaten Pakistan's billion dollars in aid we send every year.

There are risks to Trump's policy and some contradictions, as O'Sullivan points out.  But compared to Obama's indecisiveness, Trump's policy proposals are a breath of fresh air.