N.L.R.B. v. Jamaica Towing, Inc.

Holding that "hallmark" violations of NLRA "include such employer misbehavior as the closing of a plant or threats of plant closure or loss of employment, the grant of benefits to employees, or the reassignment, demotion or discharge of union adherents" and lesser violations "include such employer misconduct as interrogating employees regarding their union sympathies, holding out a `carrot' of promised benefits, expressing anti-union resolve, threatening that unionization will result in decreased benefits, or suggesting that physical force might be used to exclude the union"