The institute’s analysts predict the caliphate may be readying for an onslaught, possibly timed for the end of the holy month of Ramadan on Monday or during the Eid holiday celebrations this week. The aim would not be to seize Iraq’s capital, which has a very large Shia population with every incentive to fight to the death against an organization that slaughters Shia prisoner en masse. The purpose of the Islamic State offensive would be to sow mayhem and to keep Iraq’s state apparatus from recovering from its stunning defeats in June, when it lost control of Mosul, the second largest city in the country.

A sustained bombing campaign could well finish off the government of the embattled Prime Minister Nuri al-Maliki, who is still trying to cling to power, despite indications that even Iran, his main foreign backer, thinks it is time for him to step down.

There has been a burst of attacks by bombers wearing suicide vests and also car blasts “along avenues of approach to the capital and also within Baghdad proper,” the institute notes in an intelligence update. Most significantly, the analysts say, IS has been launching coordinated suicide attacks like those on July 19 which involved half-a-dozen or more blasts in a day.