India, Sept. 6 -- When the clock runs out on Monday, universities that have run academic exchanges with Iranian institutions, families that use remittance services to send money to relatives in Tehran, and conference organisers who have worked with Iranian counterparts for decades will find their authorisations gone, replaced by nothing. The window that the Trump administration's Treasury Department opened to wind down those relationships closes September 8, and no general licence will replace it.

The deadline is the sharpest edge yet of "Operation Economic Outcast," the sweeping sanctions campaign Treasury Secretary Scott Bessent unveiled on August 24, describing it as "the single greatest financial offensive ever marshalled against an...