Recent reports of campaigns designed to discourage potential employers from hiring Trump Administration officials raise the question of whether a private sector employer would have any jeopardy for going along with such a boycott. The answer depends upon where the act takes place. Fifteen states, plus Puerto Rico and the District of Columbia, prohibit discrimination or retaliation against employees or applicants on the basis of political affiliation or activity. Some states have more limited, but potentially applicable laws. (For a thorough analysis of these laws see Volokh). Other states may recognize doctrines, such as violation of public policy or engaging in lawful activities, that could be fashioned into a reasonable argument for employee protection.
Political parties are not mentioned in the Constitution of the United States. What is mentioned is “…the right of the people to peacefully assemble, and to petition the Government for a redress of grievances.” (Amendment I) In addition to freedom of speech, this provides some protection from governmental interference with the right of persons to join and support political parties. Indeed, the current suits against alleged gerrymandering to favor one party over another, use this type of argument to create a constitutional violation out of interfering with an institution unmentioned in the document.
The so-called right of free association has been recognized as covered by the First Amendment protections, thereby giving additional heft to arguments that political party participation should enjoy some special protection, at least from government interference. Thus, local governments cannot officially prefer members of one party over another, or retaliate against employees for their participation in political campaigns, subject to certain limitations. Private employers, except in the locations where there are statutes, have not had to worry about this category of discrimination. It would not be surprising, however, to see a disappointed applicant or discharged employee make an argument that the presence of these rights in the First Amendment (and in many state constitutions) establishes a clear public policy to protect political activity, including service to the nation by joining whatever administration is currently in power. On the other hand, employers also enjoy the right to associate with whom they choose, and could argue that forcing a rock-ribbed conservative to hire a socialist activist would violate the rights of the employer. Or forcing a liberal think tank to hire a Trump administration true believer would be inconsistent with the free association model.
Given that many former administration officials seek post-government work in the District of Columbia, in New York City, at Yale, or at think tanks in coastal states, they are likely to find themselves with at least theoretical protection against political discrimination. Employers who accede to the suggestions to boycott administration officials may find themselves subject to discrimination claims, with uncertain results.
 Arizona, California, Colorado, Connecticut, Louisiana, Minnesota, Missouri, Nebraska, Nevada, New Mexico, New York, South Carolina, Utah, West Virginia, Washington.