It’s not just former Vice President Joe Biden’s campaign experiencing a resurrection in light of his strong Super Tuesday performance.

After telling CNN reporter Manu Raju Wednesday morning that he told President Trump that Biden will be “tough” to beat in the general election, Sen. Lindsey Graham (R-SC) appeared to suggest that Senate Republicans plan to go after the former vice president for his son’s tenure on the board of Ukraine energy company Burisma.

“If you are going to run for President, and you were in charge of the Ukrainian anti-corruption campaign as vice president, and your son is sitting on the most corrupt company in the country while you’re trying to clean up the country, yeah that will come up,” Graham said.

When asked whether he plans to launch an investigation in the Senate Judiciary Committee, Graham responded that Sen. Ron Johnson (R-WI) is “doing it.”

Sen. Lindsey Graham: "If you're going to run for President and you were in charge of the Ukrainian anti-corruption campaign as VP and your son's sitting on the most corrupt company in the country while you're trying to clean up the country — yeah, that'll come up." pic.twitter.com/tTyBoxmmOG — The Hill (@thehill) March 4, 2020

On Monday, Johnson signaled to his colleagues on the Senate Homeland Security and Governmental Affairs committee in a letter that he wants to begin issuing subpoenas as part of his probe into Hunter Biden’s work for Ukraine energy firm Burisma. Johnson’s investigation piggybacks off of debunked allegations that the DNC colluded with the Ukrainian government in 2016 to damage Trump’s presidential candidacy.

Last week, Senate Democrats attempted to block a subpoena for testimony for Andrii Telizhenko, a former staffer at Ukraine’s embassy in Washington who has stoked baseless allegations of Ukrainian government interference in the 2016 election.

Politico reporter Andrew Desiderio tweeted Wednesday morning that Johnson said Biden “never adequately answered” Ukraine scandal-related questions that Democratic primary voters would want “satisfactorily answered.”

“These are questions that Joe Biden has never adequately answered,” Johnson tells us. — Andrew Desiderio (@AndrewDesiderio) March 4, 2020

TPM reached out to Biden’s campaign for comment. We will update this post if we hear back.