President Obama's new strategy in Afghanistan is a reminder that sometimes politicians make campaign promises they can't keep.

Obama doesn't believe military might is the best way to effect change abroad, and his military strategy has reflected as much: Back in 2008, then-Sen. Obama promised to get out of Iraq and increase troops in Afghanistan with the hopes of getting out of there soon, too. He also pledged to close the Guantanamo Bay prison in Cuba. In exchange, he promised to invest in nonmilitary assistance and focus more on diplomacy. 

"At some point, a judgment must be made," he said in a flagship speech on the campaign trail in July. "Iraq is not going to be a perfect place, and we don’t have unlimited resources to try to make it one." 

Needless to say, those plans haven't panned out. In just a few sentences, The Washington Post's Greg Jaffe's excellent piece about Obama's dwindling chances to bring Afghanistan troops home sums up the reality he's instead facing: 

Obama has launched military strikes in seven countries. He ended a war in Iraq only to recommit thousands of American troops there when Islamic State insurgents routed the U.S.-trained Iraqi army in Mosul. A few weeks later, he ordered the U.S. military to start bombing Islamic State strongholds in Syria. Afghanistan has been the one constant that spans his two terms office.

There are a variety of reasons things haven't gone Obama's way — some arguably his making, others he had no control over. Congress and other countries blocked many transfers of prisoners from Guantanamo Bay (though critics of closing Guantanamo would say this was predictable); whether the withdrawal from Iraq helped the Islamic State is much debated; and Iraq and Afghanistan's political turmoil hasn't made it easy for the president to exit those two countries.

But the bottom line is that Obama's campaign promises, which sounded feasible enough at the time to those who agreed with his worldview and rewarded him for it, relied on too much he couldn't control. He stepped into office in 2009 with a grand strategy — in his words, "to lead this country in a new direction" — but much has conspired to keep America's Middle East policy focused on Iraq and Afghanistan.

Critics, of course, would say he should have anticipated as much and not made promises he couldn't keep. But making promises one perhaps cannot keep isn't necessarily a bad thing, argued Jon Alterman, the director of the Middle East program at the bipartisan, nonprofit Center for Strategic and International Studies. Alterman likened a campaign promise to a New Year's resolution — useful even if you don't keep it.

"It gives you a set of goals, it helps you remember what your priorities are," he said, "but it's no guarantee of success."

And rarely do U.S. presidents have guarantees of success, especially those hoping to untangle some of the world's most complicated, long-running geopolitical dramas. If Obama had been able to fulfill all of his Middle East campaign promises, Alterman said, it would have been rather remarkable, when you look at the course of history.

Even then, though, the question is whether making such promises is a good idea. Politically, of course, there is pressure to make hard-and-fast declarations about what you will do as president. That was certainly the case when it came to getting out of an unpopular war in Iraq during the 2008 election and also Afghanistan in 2012.

A more realistic campaign promise would have been along the lines of what he said Thursday.

"I meet regularly with my national security team, including commanders in Afghanistan, to continually assess, honestly, the situation on the ground — to determine where our strategy is working and where we may need greater flexibility," he said.

Obama didn't say that back then, of course, and he's reaping the consequences now. As his nearly seven-year struggle to fulfill his campaign promises abroad reminds us, much of what our 2016 contenders say they'll do — on day one or otherwise — is more realistically out of their hands.