Habeas corpus is the final appeal to the federal courts after you have been convicted and lost all your appeals in state court. A habeas corpus claim must be based on violation of your federal constitutional rights. Non-constitutional claims such as routine decisions by the trial court to admit or exclude evidence may not be considered in habeas corpus. Ineffective assistance of counsel and failure of the Government to disclose evidence favorable to the defendant are typical habeas claims.
Before you can go into federal court you must exhaust all your state remedies. This means that you must pursue every available avenue of appeal to every possible court in the state system. If you are convicted in Washington, you must file a direct appeal either to the Court of Appeals or the Washington Supreme Court and then if you lose, you must seek further relief by filing what is known as a personal restraint petition. If you fail to pursue every available avenue of appeal in the state system, the federal court will dismiss your habeas corpus petition without ever hearing your claim.
Federal review on habeas corpus is very limited. The federal court looks to see whether or not the state appellate court that reviewed the conviction made an objectively unreasonable application of established federal law or an unreasonable determination of the facts. In other words, it is not sufficient to simply show that the state appellate court made an error. In order to gain relief, the habeas petitioner must show that the state court decision was so egregious as to be objectively unreasonable.
Federal courts are organized by district. A habeas petition is filed in the district where the conviction occurred. The petition must be filed within one year of the time that the state court conviction became final or the federal court will dismiss it as time barred. The petition must be supported by facts showing that the petitioner was deprived of federal constitutional rights. For example, if you are claiming that your trial attorney was ineffective, your petition must specify the errors the attorney made and the manner in which those errors might have affected the outcome of the trial. You cannot bring up claims in the habeas petition that have not previously presented to the state court nor, generally speaking, may you bring up new evidence. If you try to bring up a new claim, the federal court will dismiss the petition for failure to exhaust state remedies. If you try to bring up new evidence in support of a previously pleaded claim, the federal court will refuse to hear it. Nor can you bring up novel legal theories in a habeas corpus petition as claims may only be based on established federal law as previously announced by the United States Supreme Court.
Needless to say habeas corpus is a highly technical and narrow remedy that should only be pursued as a very last resort. In general, federal courts are more likely to give careful and immediate attention to habeas petitions only in the most serious cases. Those with the greatest likelihood of success are facing the death penalty because of the special rules and procedures that are applicable only in capital cases.