The rules regarding whether an alien is subject to mandatory detention are found within the Immigration and Nationality Act (INA), particularly Section 236(c). Under section 236(c), mandatory means what it says: the individual must be taken into custody and detained; there is no discretionary release. People with criminal records are usually the ones most vulnerable to detention without bond.
On the other hand, there are a few strategies and methods that skilled immigration attorneys use to rescue aliens from immigration custody.
Argue that not subject to mandatory detention.
All too often, people will just throw their hands up and resign themselves to prolonged custody anytime an immigration officer classifies an alien as subject to mandatory detention. Keep in mind that the government is invoking a section of the law that like everything else is subject to interpretation. That's why we have courts and that's why there are immigration lawyers who practice removal litigation. Under certain circumstances, an immigration judge may entertain a "Joseph hearing" during which he/she will rule whether the individual is "properly included" within the mandatory detention rules. If mandatory detention has been improperly applied to the alien, he/she may be eligible for bond.
Just Calling Something a Crime Involving Moral Turpitude or Aggravated Felony does not make it so.
The law is very sensitive. CIMTs and AF are legal terms of art, but not all state offenses will necessarily constitute or meet the federal or caselaw definitions of deportable or inadmissible types of crimes. An attorney will conduct an extensive investigation of the alleged grounds and compare them to what the client was convicted of. It is not surprising to learn that in many cases, an argument can be raised that a conviction does not constitute what the government says it does. If that argument can be persuasively made, an Immigration Judge may rule that the alien is not subject to mandatory detention.
Mandatory detention only applies to individuals released from custody after October 8, 1998.
Are there any circumstances that warrant release?
This is very limited but the Immigration and nationality Act (INA) does authorize the government to parole or release an alien under certain circumstances. Release is contemplated under this section when the release is necessary to protect a witness, a potential witness, or a person who is cooperating with an investigation into major criminal activity.
Do not assume that ICE is on your side and will set a bond because you happen to be a permanent resident or the officer seems nice. In this climate, it is easier for the government to classify a criminal alien as someone who is subject to mandatory detention rather than to release the person into the public and then be held responsible if that person later absconds or worse, harms somebody. A skilled attorney, however, may ask for a Joseph hearing to argue that the person is not subject to mandatory detention, employing some of the arguments and points raised above.