In a criminal law context, bail is most often thought of as the posting of security to ensure the presence of an accused at subsequent judicial proceedings—that is, "to obtain the release of (oneself or another) by providing security for future appearance." The term itself is less frequently used now, however, due in part to the practice of release on personal recognizance, which consists of permitting an individual to pledge his word, rather than his property, for his future appearance. Moreover, today, an individual's release pending subsequent criminal proceedings is often predicated on conditions other than, or in addition to, the posting of an appearance bond, secured or unsecured. As a consequence, rather than speaking of bail, existing federal law refers to release or detention pending trial, to release or detention pending sentencing or appeal, and to release or detention of a material witness. This is an overview of federal law in each of these areas, as well as in the area of extradition from the United States to another country. An individual released prior to trial remains free under the same conditions throughout the trial until conviction or acquittal, subject to modification or revocation by the court. For that reason, the term pretrial release is understood to include all pre-conviction release, both before and during trial. Under existing federal law, an individual arrested under federal authority must be brought before a magistrate or judge without unnecessary delay. Any federal or state judge or federal or state magistrate may qualify. The magistrate judge may order an individual accused of a federal crime either released or detained prior to trial and conviction. The law affords the judge or magistrate four options, which it places in descending order of preference. First, he may release the accused on personal recognizance or under an unsecured appearance bond, subject only to the condition that the accused commit no subsequent federal, state, or local crime and that he submit a sample for DNA analysis. Second, he may release the accused subject to certain additional conditions. Third, he may order the accused detained for bail revocation, parole revocation, probation revocation, or deportation proceedings. Fourth, he may order the accused detained prior to trial. If the magistrate or judge does not initially release the accused on personal recognizance or conditions, a hearing on the release of the accused must be held "immediately" upon the individual's first appearance before the judge or magistrate. The accused or the government may request that the hearing be postponed for up to five days—up to only three days when the postponement is granted at the government's behest. The accused is entitled to assistance of counsel at the hearing and to the appointment of counsel if necessary. The accused may testify at the hearing and present and cross-examine witnesses. Evidence may be introduced at the hearing without deference to the rules that apply at a criminal trial. The decision to release an accused on personal recognizance or unsecured appearance bond rests upon a determination that the accused poses no risk of flight and no risk of danger to the community or any of its inhabitants. The decision requires consideration of four factors: (1) "the nature and circumstances of the offense … ; (2) the weight of the evidence against the person; (3) the history and characteristics of the person … ; and (4) the nature and seriousness of the danger to any person or the community that would be posed by the person's release…" If the judge or magistrate concludes that personal recognizance or an unsecured appearance bond is insufficient to overcome the risk of flight or to community or individual safety, he may condition the individual's release on a refrain from criminal activity, collection of a DNA sample, and the least restrictive combination of 14 conditions. Under the appropriate circumstances, the "community" whose safety is the focus of the judge's or magistrate's inquiry need not be limited geographically to either the district or even the United States. The 14 statutory conditions are third-party supervision; seeking or maintaining employment; meeting education requirements; observing residency, travel, or associational restrictions;* avoiding contact with victims or witnesses;* maintaining regular reporting requirements;* obeying a curfew;* adhering to firearms limitations;* avoiding alcohol or controlled-substance abuse; undergoing medical treatment; entering into a personally secured appearance agreement; executing a bail bond; submitting to afterhours incarceration; and complying with any other court-imposed condition. Section 3142 requires the judge or magistrate to impose electronic monitoring and several of these conditions (noted with an asterisk above) when the accused is ineligible for release on personal recognizance or an unsecured bond and is charged with one of several sex-related offenses against children. Several defendants have successfully challenged this mandatory requirement on Due Process Clause or Excessive Bail Clause grounds. Notwithstanding the explicit conditions that seem to contemplate requiring an accused to post security for his release or face detention, Section 3142 provides that "the judicial officer may not impose a financial condition that results in the pretrial detention of the person." The courts have resolved the apparent conflict by essentially construing the provision to apply when the financial condition is not calculated to result in pretrial detention but is a collateral consequence of the court's determination of the amount necessary for safety and to prevent flight. As the Ninth Circuit explained: Several other circuits have addressed the apparent violation of §3142(c)(2) that arises when, as in Fidler's case, a defendant is granted pretrial bail, but is unable to comply with a financial condition, resulting in his detention. It may appear that detention in such circumstances always contravenes the statute. We agree, however, with our sister circuits that have concluded that this is not so. These cases establish that the de facto detention of a defendant under these circumstances does not violate §3142(c)(2) if the record shows that the detention is not based solely on the defendant's inability to meet the financial condition, but rather on the district court's determination that the amount of the bond is necessary to reasonably assure the defendant's attendance at trial or the safety of the community. This is because, under those circumstances, the defendant's detention is not because he cannot raise the money, but because without the money, the risk of flight [or danger to others] is too great. The accused, however, may have to overcome the statutory rebuttable presumption of flight or dangerousness to secure his release on personal recognizance or an unsecured appearance bond. A rebuttable presumption attaches under either of two circumstances. The first occurs when, following a hearing, the judge finds probable cause to believe that the accused has committed one of the serious crimes classified as either (1) a 10-year drug offense; (2) an offense involving possession of a firearm in furtherance of a crime of violence or serious drug offense; (3) a 10-year federal crime of terrorism; (4) a 20-year human trafficking offense; or (5) a designated sex offense committed against a child. The second set of circumstances giving rise to a rebuttable presumption occurs when, following a hearing, the judge finds probable cause to believe that the accused previously committed a qualifying offense, much like those just described, while on bail, and for which he was convicted or released from imprisonment within the last five years. "[T]he presumption reflects Congress' substantive judgment that particular classes of offenders should ordinarily be detained prior to trial." An accused must present some rebuttal evidence, no matter how slight, in order to the escape the presumption. Nevertheless, the prosecution bears the ultimate burden of establishing that no series of conditions is sufficient to negate the risk of the accused's flight or dangerousness—by a preponderance of the evidence in the case of flight and by clear and convincing evidence in the case of dangerousness. Unless he holds the accused for revocation or deportation proceedings, the judge or magistrate may decline to release the accused on conditions only if he finds that no condition or series of conditions will provide reasonable assurance against flight or dangerousness. The third option available to the judge or magistrate if the accused poses a flight or safety risk is to order him detained for up to 10 days to allow for a transfer of custody for purposes of bail, probation or parole, or deportation revocation proceedings. Otherwise applicable bail provisions come into play if the accused has not been transferred within the 10-day deadline. Finally, having exhausted the other options—release of personal recognizance, release under conditions, and release for other proceedings—the judge or magistrate may order the accused detained prior to trial. Although pretrial detention is the least statutorily favored alternative in the federal pretrial bail scheme, 72.7% of those accused of federal crimes and presented to a federal judge or magistrate are detained prior to trial. The judge or magistrate may order pretrial detention upon determining, after a hearing, that no combination of conditions will be sufficient to protect against the risk of flight or threat to safety. The government has the option of petitioning for pretrial detention under two circumstances. The first consists of instances in which the accused is charged with one or more designated serious federal offenses, that themselves create a rebuttable presumption that no set of conditions will guarantee public safety or prevent the flight of the accused. The second consists of instances in which the defendant poses a serious safety or flight risk, regardless of the crime with which he is charged. Offense- D riven D etention .