I work for a news organization whose social media policy cautions against expressing personal or political views that might impinge on the organization's credibility or imply bias. I know that the NLRB defends political speech in terms of workplace organizing and conditions, but what is the status of workplaces ability to curtail employees free speech on their personal accounts? Is it simply that private employers can do so freely? An excerpt: "You must not advocate for political or other polarizing issues online. This extends to joining online groups or using social media in any form (including your Facebook page or a personal blog) to express personal views on a political or other controversial issue that you could not write for the air or post [organization]."