WASHINGTON (AP) — A federal prosecutor tapped by President Joe Biden to become a U.S. district judge in Kansas has withdrawn from consideration, citing the nearly two-year wait for action on his nomination.

Jabari Wamble is Biden's second judicial nominee to withdraw this month. Attorney Michael Delaney backed out of consideration for the Boston-based 1st U.S. Circuit Court of Appeals last week in a rare judicial defeat for the Democratic president. Delaney did not have enough support in the Senate Judiciary Committee to send his candidacy on to the full Senate for confirmation.

Wamble wrote to Biden that he had been "humbled and honored by the faith you placed in me with this nomination" but said he was withdrawing from consideration for appointment to the U.S. District Court for Kansas.

"My path to this nomination began more than 18 months ago and after careful thought and consideration I feel that it is best for me to continue my work at the United States Attorney's Office in the District of Kansas," he wrote in a letter dated Tuesday.

The White House on Wednesday did not offer an explanation for Wamble's withdrawal. But one official familiar with Wamble's confirmation process said he was expected to receive a "not qualified" designation from the American Bar Association, which rates candidates for federal judgeships.

The ABA has not issued a formal rating for Wamble. The official spoke on the condition of anonymity to discuss a process that is not public.

Biden is proud to have nominated Wamble, said White House deputy press secretary Andrew Bates, who called him "a deeply qualified attorney who has served with distinction as a prosecutor at the state and federal level in Kansas, who received his undergraduate and law degrees from the University of Kansas, and who has dedicated his life to serving the people of Kansas."

Wamble initially was nominated for a circuit court vacancy earlier in the Biden administration, but the nomination expired before he could be confirmed by the Senate. He later was nominated for the district court seat in Kansas.

Politico was first to report Wamble's withdrawal.

Carl Tobias, a University of Richmond law professor who specializes in the federal judiciary, said he was "puzzled" by the withdrawal. Tobias said Wamble seems well qualified after more than a decade of experience as an assistant U.S. attorney, often a route to becoming a federal judge.

"Lots of people go on the federal bench in Democratic and Republican administrations with similar qualifications to Wamble, so it's mystifying to me," Tobias said.