With this week's news that U.S. military will scale down its operations in Afghanistan and eventually withdraw in 2016, a lot of people are wondering what this will actually mean. Here, The Post's Kabul bureau chief Kevin Sieff spells out five things you need to know.

1. This might be the Afghan military's war now – but only because 140,000 Western troops failed to defeat the Taliban.

Some 9,800 American troops will remain in Afghanistan at the beginning of next year. To put that number in perspective, there were over 100,000 U.S. troops here in 2011 (along with 40,000 troops from other nations) during the peak of the American-led surge. They occupied more than 700 bases across Afghanistan, some of them the size of small cities.

Through 2011, those troops were committed primarily to a unilateral fight against the Taliban. Many U.S. officials hoped that with so much combat power, Western forces could deal a knockout blow to the Taliban. By 2012, it was clear that such a blow had not been dealt. Insurgents were able to use sanctuaries in Pakistan to regroup and regenerate.

Reconciliation efforts failed and the war appeared to have no short-term diplomatic or military solution. The White House needed a new "New Strategy."

2.The Afghan military and police have become much better fighting forces, but you can't fight without guns or fuel.

By 2012, it became very clear that the only sustainable way to continue applying pressure on the Taliban was to build an effective Afghan army and police. But after a decade of war, the Afghan security forces remained notoriously incompetent – often mocked by both their American counterparts as well as Afghan civilians.

As the U.S. mission pivoted to “advising and assisting” the Afghan military and police grew in both size and ability. By 2013, they were conducting independent missions against the insurgency. But soldiers and police still struggle to handle even rudimentary logistical issues – how to get water or fuel or guns; how to repair vehicles; how to keep their generators running. With more sophisticated institutions, like the Afghan Air Force, those struggles are even greater.

Fast forward to 2016, when the last American troops leave: Will the Afghan military be able to sustain itself with essentially no foreign assistance? That’s a question a lot of Afghan and U.S. officials are asking today.

3. The Afghan economy was kept afloat by foreign assistance. It is not clear what happens if those funds dry up.

Observers often focus exclusively on the fighting ability of the Afghan army and police. But an even more pressing question is how those institutions will be funded. Right now, the country’s security forces cost $6.5 billion annually. Most of that funding comes from the United States. The U.S. withdrawal means an increasing reliance on Afghan forces, with their significant price tag. But how long will Washington be willing to shoulder that cost, particularly as oversight diminishes? This year, Congress cut America’s contribution to Afghanistan’s non-security budget in half.

While the West endeavored to create a healthy Afghan economy, capable of bankrolling its own institutions, the country’s budget shortfall continues to grow just as foreign assistance begins to dry up. Some Afghan officials worry they are only months away from being unable to pay government salaries.

4. The Taliban is the least of the Afghan government's problems.

Another false assumption made by many is that the Taliban is the only threat to a stable Afghanistan. While the Taliban remain capable of assuming power in remote districts and executing high-profile attacks in urban areas, it remains unlikely that the group could retake Kabul oroverthrow the Afghan government. For now, a greater threat to the country comes from the government itself. With so many internal divisions – between ethnic, political and tribal groups – if the Afghan government is not seen as being inclusive, its legitimacy could be challenged, perhaps leading to widespread violence.

The power brokers in Afghanistan’s civil war remain prominent figures in Afghan society and politics today, and many say they could amass independent fighting forces if necessary. Outside of possible violence, a faltering government could have devastating consequences for what is already a fragile economy. President Hamid Karzai, often lambasted as being hostile and self-interested, was uniquely capable of uniting rivals under the same tent. It’s unclear whether his successor, either Abdullah Abdullah or Ashraf Ghani, has that same ability.

5. There were some big gains over the last decade, and the U.S. deserves credit for them. But now the big problem is whether they can be sustained.

Because so much about Afghanistan’s future remains uncertain, it’s sometimes easy to forget the gains of the last 12 years. More than 2.5 million girls are in school (there were nearly none under the Taliban’s reign). There is a free press that openly criticizes the political establishment. More than 6 million people voted in the first round of the country’s presidential elections last month. Millions of people have cellphones in their pockets. In Kabul, a generation is now growing up with Internet access.

Those are all products of the US effort here. But they’re also gains that could be lost if the country again descends into chaos after 2016.

President Obama said Tuesday that “Afghanistan will not be a perfect place.” That’s already abundantly clear. But Afghans wonder what kind of imperfection the United States is willing to accept as it concludes its longest war. Which gains are U.S. officials willing to see reversed? What level of instability is acceptable? And what do those imperfections mean, in practice, to the people who live here?