MSNBC s Chris Hayes said House Oversight Committee chair James Comer (R-Ky.) has just had one of his most humiliating failures yet in his investigation of the Biden family.

On Tuesday, Hunter Biden signaled via his attorney that he was willing to testify in the impeachment probe into his father, President Joe Biden , but only if he could do so in a public hearing. He argued Republicans could use a closed-door setting to manipulate the facts.

Comer rejected the offer, claiming the presidents son was trying to play by his own rules.

On All In Wednesday night, Hayes said, Hunter Biden has called their bluff.

He added, Youd think that would be precisely the sort of dramatic, confrontational moment Republicans have been waiting for.

After years building up to this climactic moment, the opportunity to grill Hunter Biden under oath in front of the country, Republicans retreated from their own battle? This is absolutely the most humiliating loss for James Comer yet, and there have been a lot, Hayes said.

Comer and other House Republicans have been investigating the Biden family for nearly a year. They opened an impeachment inquiry into Joe Biden in September, centered on their allegations that the president was improperly involved in his sons foreign business dealings.

They have not uncovered evidence of wrongdoing by the president.

A public impeachment inquiry hearing in September prompted mockery from Democrats and embarrassing headlines for Republicans after their own expert witnesses said there wasnt enough evidence to impeach Joe Biden.