A more thorough explanation:

Recusal is when a judge or prosecutor removes themselves from a case because of a conflict of interest. This means they have a personal or professional connection to someone involved in the case that could affect their ability to be impartial.

For example, if a judge used to work for a law firm that is representing one of the parties in a case, they would need to recuse themselves. Similarly, if a prosecutor has a close relationship with someone who is being investigated, they would need to recuse themselves.

One example of recusal happened in 1990 when U.S. Attorney General Richard Thornburgh removed himself from a drug investigation involving public officials. One of his former aides was a subject of the investigation, so he had a conflict of interest.

Another example occurred in 2008 when U.S. Attorney General Michael Mukasey recused himself from an investigation into the Alavi Foundation's ties to Iran. He had previously represented them in court when he was a private lawyer, so he had a conflict of interest.

These examples show that recusal is important to ensure that judges and prosecutors are fair and impartial in their decisions. It helps to prevent any bias or conflicts of interest from affecting the outcome of a case.