Crowdsourcing. It’s been used for everything from handicapping the next election to making a kick-ass encyclopedia to building a better movie recommendation tools for Netflix. America’s spy agencies are hoping it can help ‘em predict what’s going to happen on the world stage next. In other words, Washington’s next sharp-eyed intelligence analyst could be you. An early test of the system starts this week.

On Friday, Applied Research Associates, Inc will launch the Aggregative Contingent Estimation System (ACES), a website that lets members of the public test out methods to crowdsource...