A union began campaigning to organize employees working at a store that Lechmere, Inc. (defendant) owned in a shopping plaza. Organizers put handbills on windshields where employees usually parked, in the parking lot jointly owned by Lechmere and other plaza stores. Lechmere personnel told organizers that Lechmere prohibited soliciting or distributing handbills on the property and asked the organizers to leave. The organizers moved to a public grassy strip nearby and passed out handbills to drivers at times when most were employees, obtained employee addresses and sent out mailings, and tried calling employees at home. But altogether, those efforts produced just one signed union authorization card. The union filed a complaint alleging that excluding organizers from the property violated the Wagner Act, and the National Labor Relations Board (NLRB) (plaintiff) found Lechmere’s exclusion unlawful. Lechmere appealed. The circuit court affirmed, but the Supreme Court granted review.