During his confirmation hearing Thursday, Ben Carson repeatedly refused to guarantee that money from the Department of Housing and Urban Development would not go to benefit President-elect Donald Trump or his family.

“Among the billions of dollars that you will be handing out in grants and loans, can you just assure us that not one dollar will go to benefit either the president-elect or his family?” Sen. Elizabeth Warren (D-Mass.) asked.

“I can assure you that the things that I do are driven by a sense of morals and values,” Carson responded. “And therefore I will absolutely not play favorites for anyone.”

Carson is Trump’s nominee to run HUD, an anti-poverty agency charged with federal affordable housing efforts.

When Warren pressed him again, Carson again insisted on his own personal neutrality, instead of agreeing to avoid sending money to the president and his family. “It will not be my intention to do anything to benefit any American, particularly, it’s for all Americans, everything that we do,” Carson said.

“If there happens to be an extraordinarily good program that works for millions of people and it turns out that someone that you’re targeting is going to make $10 from it,” Carson added, he wouldn’t make a big fuss over the $10.

“The problem is that you can’t assure us that HUD money ― not of $10 varieties but of multimillion-dollar varieties ― will not end up in the president-elect’s pockets,” Warren responded. “And the reason you can’t assure us of that is because the president-elect is hiding his family’s business interests from you, from me, from the rest of America. And this just highlights the absurdity and the danger of the president-elect’s refusal to put his assets in a true blind trust.”

“He knows, he the president-elect knows, what will benefit him and his family financially,” Warren continued. “But the public doesn’t. Which means he can divert taxpayer money into his own pockets without anyone knowing about it.”

Later in the hearing, Sen. Thom Tillis (R-N.C.) criticized Warren’s line of questioning, saying it would start a “fake news cycle.”

“I doubt seriously that scenario will ever come up,” Tillis said.

Trump owns a stake in a 46-building affordable housing development in Brooklyn overseen by HUD.

There is a long tradition of American anti-corruption thinking that believes policymakers should work to reduce the appearance of corruption and build public faith in political institutions by eliminating conflicts of interest.