GOP senator calls for Judiciary Committee to subpoena Donald Trump Jr., Hunter Biden

Curtis wants an investigation into the alleged personal use of political ties.

Utah Republican Sen. John Curtis is calling on Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, and Ranking Member Dick Dubin, D-Ill., to subpoena both Donald Trump Jr. and Hunter Biden as part of an investigation into "the use of presidential family relationships for private financial benefit, preferential treatment or access by domestic and foreign interests" that Curtis is urging the senators to open.

Curtis' letter comes after he posted a video on X Friday saying that reports that Donald Trump Jr.'s two-day wedding afterparty in May had been funded by a Russian oligarch with close ties to Russian President Vladimir Putin "stink" and are "corruption." He promised further action on the topic.

President Donald Trump said last week that his son had repaid the oligarch for the afterparty costs, though no evidence of that alleged repayment has been publicly offered.

"As I understand it, he paid them back. He didn't want to have that, so I hear he paid them back. A person that he knows pretty, I guess a friend of his, gave him a wedding party. That's very common," the president said .

"The country should not have to accept one standard for the family of a Republican president and another for the family of a Democratic president. Nor should congressional oversight begin and end when control of the White House changes hands," Curtis writes in the letter .

"I therefore respectfully request that the Senate Judiciary Committee launch an investigation into the use of presidential family relationships for private financial benefit, preferential treatment, or access by domestic and foreign interests," Curtis' letter continued. "As part of that investigation, I urge the Committee to subpoena Donald Trump Jr. and Hunter Biden to testify regarding their past business dealings, relationships with foreign individuals and entities, gifts, or other benefits they have received, and any instances in which their relationship to the President was invoked or understood to provide value."

Hunter Biden, the youngest son of former President Joe Biden, has faced years of Republican and congressional scrutiny over unproven claims that he and his father, who was then vice president, allegedly pressured a Ukrainian oligarch to pay them millions of dollars to orchestrate the firing of a Ukrainian prosecutor who at the time was investigating Burisma, the energy company of which the oligarch was CEO. Hunter Biden sat on Burisma's board at the time.

Sen. Durbin said Tuesday that he supports Curtis' "good faith request" for the investigation.

"Corruption must never be tolerated," Durbin said in a statement , in part. "To ignore this is to run the risk of being complicit. I will join in supporting Senator Curtis’ request of the Judiciary Committee."

An ABC News request for comment sent to Sen. Grassley did not immediately receive a response.

Curtis is not a member of the Judiciary Committee and would not be involved in any vote to subpoena Hunter Biden or Donald Trump Jr.