The main point of last week’s presidential report on America’s progress in Afghanistan was no surprise: We’re making “fragile” progress in our nine-year war there, but not enough. Yet it’s what President Obama and his advisers aren’t saying about Afghanistan that’s vital to making up our minds on whether this war is worth it.

First, the brutal Afghan winter leaves us stuck in a dynamic where every fall our generals and strategists make an adjustment, then must wait for spring and summer to see if it worked. It’s a chess game in which the players get one move a year, and it’s been going on since 2002. This makes progress, if any, hard to measure — and frustrates our soldiers and generals, who must wait four months after every operation against the Taliban to see if it pays off.

Second, we’re fighting an enemy, al Qaeda and its allies, who lost in Iraq — and are determined not to repeat the mistake. They’ve studied the Petraeus surge and have been busy taking countermeasures, like applying more terror to keep locals from joining our side. This guarantees that progress is slower than it was in Iraq.

There are also positive developments that no one talks about.

First, the Marines are taking over. In June 2008, 3,700 Marines were in-country. Today, it’s 20,000-plus — and don’t be surprised if that number grows. They’re the secret weapon in Obama’s Afghan surge, proven counterinsurgency warriors who literally wrote the book on such wars (the 1940 “Small Wars Manual”). The places where the Marines go, like Marjah in Helmand, Afghanistan’s most violent province, and Sangin (where they took over from the British in September), are seeing the fastest turnaround.

No surprise: Marines are trained to be the cops on the beat who get to know not only every corner of the neighborhood, but also who are the real bad guys and who’s merely bluffing — and who’s ready to help keep law and order.

Unfortunately, the Army so far has acted more like the cop in the prowl car — rolling out in convoys to and from their secure bases (which makes them easy bait for IEDs and other roadside bombs) and hitting the enemy — but so eager to get back to base that they miss much of what’s really happening on the ground.

High command has surely noticed the difference, even if no one’s saying much about it. Expect to see the Marines doing more in the coming year.

Second, our other secret asset is the Afghan National Army — and not just in combat.

We’ve made the 140,000-strong force the country’s one functioning institution: fearless and tolerably honest. Its generals are just about the only Afghan officials with a sense of loyalty to the country as a whole, not just to their tribe or tribal leaders. If we let them handle more of provincial administration, like dealing the local shuras or village councils, as well as security, we can make the Karzai brothers irrelevant (and less of a liability until they leave the scene in 2014).

Third, success in Afghanistan is the key to defeating terrorism in Pakistan, not the other way around.

Obama’s policy has been to pressure the Pakistan government in hopes it will secure the border with Afghanistan; that has it exactly backward. A quick talk with Gen. Jack Keane, one of the masterminds behind the surges both in Afghanistan and Iraq, will confirm what my columns have been arguing for months: When the Pakistanis see our Afghan strategy start to take hold, they’ll realize they have to jump on board and confront the terrorists in their midst.

Until now, they’ve assumed Obama will fulfill his original promise to more or less quit Afghanistan in 2011 — leaving the job undone and them to deal with a victorious Taliban. Once they sense that the game has changed and the Taliban are doomed, they’ll be eager to cooperate.

Otherwise, they know the big regional winner in a US success in Afghanistan will be India, which has already given more than $2 billion in aid — or possibly even China. They won’t want to be left behind in the scramble to help a stable Afghanistan.

For now, our Pakistan policy is floundering, as the “outing” that forced us to pull our CIA head of station shows. We have a smart new ambassador in Islamabad, Cameron Munter, a protégé of the late Richard Holbrooke. Let’s give him a new agenda, as well.

Bottom line: America can still pull this one out. Our Afghan strategy is working and can also lay the foundation for stability in Pakistan as well as restore our reputation with our allies.

The big mystery: Will Obama stick to his guns on Afghanistan and stick with the current drive to work through 2014 for final victory? Or will he choose to please his Democratic political base and all but cut and run this coming summer?

If he opts for the latter, it won’t just be lives and money wasted. It’ll be proof that America is in full retreat. Don’t expect either our enemies or our friends to forget it.

Arthur Herman’s most recent book is “Gandhi and Churchill.”