Md. Code, Public Safety § 3–110

(a) A police officer may not be discharged, disciplined, demoted, or denied promotion, transfer, or reassignment, or otherwise discriminated against or threatened in regard to the police officer’s employment because the police officer:

(1) disclosed information that evidences:

(i) mismanagement;

(ii) a waste of government resources;

(iii) a danger to public health or safety; or

(iv) a violation of law or policy committed by another police officer; or

(2) lawfully exercised constitutional rights.

(b) A police officer may not be denied the right to bring suit arising out of the police officer’s official duties.

(c) (1) Subject to paragraph (2) of this subsection, a police officer has the same rights to engage in political activity as a State employee.

(2) This right to engage in political activity does not apply when the police officer is on duty or acting in an official capacity.

(d) (1) Subject to paragraph (2) of this subsection, a law enforcement agency may not prohibit secondary employment by police officers.

(2) A law enforcement agency may adopt reasonable regulations that relate to secondary employment by police officers.