Federal judges decide themselves on conflicts of interest

Donald Trump contends the federal judge presiding over a class lawsuit against Trump University has a conflict of interest and must step aside because of his "Mexican heritage." Yet nothing in federal law or codes of judicial conduct requires a judge to withdraw from a case because of his race, ethnicity, gender or other identifying criteria.

Trump says U.S. District Judge Gonzalo Curiel's ethnic background is in conflict with his proposal to build a wall along the border between the U.S. and Mexico.

Curiel has not responded publicly to any of Trump's comments. He was born in Indiana to Mexican immigrants and served as a federal prosecutor and a state judge in California before he was nominated to the federal bench by President Barack Obama in 2011.

Federal judges decide for themselves whether they should step aside because of possible biases that might influence the outcome of a case. That decision is subject to review by a federal appeals court.

Under federal law, a judge must avoid hearing a case "in which his impartiality might reasonably be questioned." This includes cases where a judge:

— Has a personal bias or prejudice against a party in the case. This can apply when a judge has expressed an opinion about the merits of a case.

— Served as a lawyer or witness in the case, or worked in private practice with someone who has.

— Has a financial interest in the case, including the financial holdings of spouses and minor children.

The American Bar Association's code of judicial conduct says a judge must disqualify himself if he has made public statements outside of court that appear to commit the judge to rule in a particular way.