It seldom occurs that there can be any conflict of jurisdiction between a federal and a state court. Any apparent conflict is usually determined by the application of the principle of comity (see above, § 143), in accordance with which one court will not interfere with or take jurisdiction over a matter as to which another court has already acquired jurisdiction. But should any conflict as to jurisdiction arise, the final authority to decide must necessarily be in the federal court, and no state court can interfere with the proceedings in a federal court, nor with officers of a federal court acting in pursuance of its orders or judgments (Riggs v. Johnson County). Redress for wrongs committed by an officer acting under the federal authority should be sought in the federal courts. But on the other hand, a federal officer, acting without authority, may be called to account in a state court for any wrong done or injury committed, subject to the power of the federal courts to review or inquire into the case for the purpose of determining whether the officer was justified by federal authority in what he has done or has attempted to do.