Stewart did not seek to compel HCEA’s compliance with this request by suggesting that noncompliance would result in any negative consequences. Although HCEA suggests that Stewart’s statements interfered with its recruiting methods, the letter did not threaten discharge or any other disciplinary response, separating it from cases finding that employer speech impermissibly interfered with core union activities like soliciting members and presenting grievances. See, e.g., NLRB v. Clinton Elecs. Corp., 284 F.3d 731, 738-39 (7th Cir.2002) (ruling that a written warning submitted to an employee for soliciting another employee to join a union violated § 8(a)(1) because the employer enforced its no-solicitation rule dis-criminatorily); NLRB v. Almet, Inc., 987 F.2d 445, 452-53 (7th Cir.1993) (<HOLDING>);, Trailmobile Div., Pullman Inc. v. NLRB, 407
holding that threatening to discharge union secretary for presenting employee grievances violated  8a1 holding that a law forbidding solicitation of union membership without obtaining an organizers card infringed on the right of speech and assembly to inform people of the advantages of union membership and persuade them to join a specific union holding union members state law claims for defamation against union preempted holding that threatening to discipline employees for not reporting union solicitation violated  8a1 holding that  8e protected an employers speech undertaken to correct any misunderstandings informing employees that their signed union cards were not confidential and that the employer retained the right to discharge or discipline employees for cause