Abstention doctrine
（重定向自Abstention doctrines）
An abstention doctrine is any of several doctrines that a court of law in the United States of America may (or in some cases must) apply to refuse to hear a case if hearing the case would potentially intrude upon the powers of another court. Such doctrines are usually invoked where lawsuits involving the same issues are brought in two different court systems at the same time (such as federal and state courts within a federal system).