It’s time to draw the line with Pakistan, whose intelligence service is reportedly colluding with the insurgent Haqqani network, an al Qaeda ally that’s been on the rampage against us in Afghanistan.

In testimony last week, Joint Chiefs of Staff Chairman Adm. Mike Mullen dropped a bombshell, saying the highly dangerous network “acts as a veritable arm of Pakistan’s Inter-Services Intelligence agency.”

Worse, Mullen alleged that, based on numbers found in militants’ cellphones, the Haqqanis’ 20-hour Sept. 13 attack on the US embassy in Kabul, which killed nearly 20 people, was done “with ISI support.”

He also tied the ISI to the Haqqanis’ truck bombing at a NATO base outside of Kabul on the 10th anniversary of 9/11, which injured nearly 80 US troops.

To sum up, he said publicly what official Washington has known for some time but been unwilling to say aloud about Pakistan: “The support of terrorism is part of their national strategy.”

The Obama administration is probably hoping that public shame and some stern-but-quiet diplomacy will bring Pakistan’s leaders to cut ties with violent extremists like the Haqqanis and Lashkar-e-Taiba. But that seems unlikely, considering history.

So, absent a sea change in Pakistani actions, what do we do?

First, we must see this news as a game-changer. Considering the threat to our soldiers, diplomats and aid workers, we shouldn’t try to put a Band-Aid on the problem. Serious surgery is required.

Taking anything less than a hard line with Pakistan will only make us look weak -- to those we’re fighting in the region, to terrorists elsewhere and to other rogue states.

First, the billions in yearly US aid to Pakistan must go on the chopping block. We can’t send taxpayer dollars to a foreign government involved in doing serious harm to Americans and US interests.

If Islamabad really breaks ties with the Haqqanis (and other extremists) and moves against them, then carefully conditioned military and other aid is worthy of reconsideration.

Next, immediately put the Haqqani network on the Foreign Terror Organization list. While largely symbolic, such a move could help target its finances. We should also step up the military and drone campaign against the group, which numbers some 5,000 to 10,000 fighters.

Plus, we should talk with our NATO allies to see if they can bring any influence to bear on Pakistan -- and rethink the pace of our withdrawal from Afghanistan until matters settle a bit on both sides of the border.

But there’s a reason Washington delayed so long in taking official notice of this problem: Playing hard ball with Pakistan has consequences.

The Pakistanis will likely dig in their heels. Cooperation, dreadful as it has been since the Osama bin Laden raid, is likely to get worse.

One powerful point of Pakistani leverage is logistics: About 50 percent of NATO supplies in Afghanistan still come overland from Pakistan.

But that percentage was much higher before we started moving supplies through the likes of Russia, Central Asia and the Caucasus (i.e., the Northern Distribution Network). If Islamabad closes southern supply routes, and we can’t boost flow from the north, we’ll have to look at reducing coalition forces and operations in Afghanistan.

The limited intelligence on the bad guys we’ve gotten from Pakistan is likely to dry up, as well. We’re basically going to be on our own here -- and will need to make do with that situation.

US-Pakistan relations were already on the rocks before this latest ISI-Haqqani twist -- not to mention yesterday’s report of a deadli Pakistani army attack on US soldiers in 2007 on the Afghan border. Now the shotgun marriage of necessity between Washington and Islamabad in fighting terrorism and extremism is probably beyond therapy. It’s time to consider a drastic change in living arrangements.

Peter Brookes is a Heritage Foundation senior fellow and a former deputy assistant secretary of defense.