W. Va. Const. art. VI, § 38

Salaries of officials cannot be increased during official terms. No extra compensation shall be granted or allowed to any public officer, agent, servant or contractor, after the services shall have been rendered or the contract made; nor shall any Legislature authorize the payment of any claim or part thereof, hereafter created against the state, under any agreement or contract made, without express authority of law; and all such unauthorized agreements shall be null and void. Nor shall the salary of any public officer be increased or diminished during his term of office, nor shall any such officer, or his or their sureties be released from any debt or liability due to the state: Provided, the Legislature may make appropriations for expenditures hereafter incurred in suppressing insurrection, or repelling invasion.