Iraq's Prime Minister Haider Al-Abadi is due at the White House on Tuesday, and it's all about the war against ISIS, the so-called Islamic State. Last year, ISIS looked like the world's most dangerous terrorist group — intent on restoring the Caliphate that once ruled all Muslims. Unique for extreme brutality and brilliant Internet propaganda, ISIS forced the US and Iran into an unlikely coalition against it. Now, ISIS is losing captured territory, its sources of money and even competent soldiers. There are signs of internal dissention. But even if it's in partial retreat, it's a likely threat in the Middle East — and to western interests — for years to come.