(CNN) It's an old tactic for an old war, but it shows the focus and emotions are fresh for the Trump administration. By suspending hundreds of millions of dollars of security aid to Pakistan, the White House is striking the first geopolitical blow of its renewed war in Afghanistan. And it's a familiar -- and not entirely unfair -- message: if the war isn't going well, Pakistan is to blame.

Afghanistan is experiencing its worst security crisis in perhaps more than a decade, with ISIS moving into its least stable areas. In the past week, Afghan officials reported that three French nationals were among a group of ISIS fighters killed by an airstrike.

US officials declined to comment on whether French nationals had managed to join ISIS's new redoubt, but ISIS are finding it easier to get a foothold in the country, partly because NATO allies are so utterly exhausted with trying to "win" in Afghanistan.

But you can't begin to win in Afghanistan unless youshave the assistance of Pakistan. Pressure on Pakistan is a keystone of something quite rare: an actual set of policy goals and objectives laid out by the Trump administration, specifically over how to "win" in Afghanistan.

It's been tried before: the Obama administration pushed Islamabad into military operations in its tribal border regions to crack down on the Pakistani Taliban, but also the Afghan Taliban and other militants the group sometimes shelters in its midst. The Obama White House offered billions worth of aid in an attempt to sway Pakistan's hand, and threatened -- often in the pages of the New York Times -- to reduce the funding if they didn't see results. Towards the end, they too froze some aid.

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