[10] In 2019, Toensing and diGenova began representing Ukrainian oligarch Dmitry Firtash in his efforts to block extradition to the United States under a federal indictment and became embroiled in the Trump–Ukraine scandal.

[16] Commenting on their role in the 1998 House of Representatives Teamsters investigation, Rep. Bill Clay, a Missouri Democrat, said, "They've become a public spectacle, which means they can't be impartial...

"[16] Toensing was a founder and board member of The WISH List, a PAC seeking to elect pro-choice Republican women to public office.

[18] Toensing was a frequent Republican commentator in the media during the Plame affair, a political scandal that led to the conviction of Scooter Libby, assistant to Vice President Dick Cheney.

[21][22] In March 2005, Toensing submitted an amicus curiae brief in support of Matt Cooper and Judith Miller, two journalists who were subpoenaed in the Plame investigation for refusing to reveal information obtained from confidential sources.

[23] Libby, the assistant to Vice President Dick Cheney, had been convicted of obstruction of justice and perjury in 2007 regarding the leak of Plame's identity.

[15] On March 19, 2018, Toensing and her husband, diGenova, were hired by President Donald Trump to serve on his legal team for the Special Counsel investigation.

Giuliani and his associates met with Lutsenko in early 2019 to discuss possible investigations of Democratic presidential candidate Joe Biden and his son Hunter.

[34][35] In July 2019, Toensing and her husband were hired by the Ukrainian oligarch Dmitry Firtash to defend him from extradition to the United States on a bribery indictment.

[44] After Firtash hired diGenova and Toensing, Giuliani acquired a statement[45] from former Ukrainian prosecutor general Viktor Shokin that falsely alleged Biden had pressured Ukraine to fire him in an effort to cover up corruption committed by himself and his son.

Shokin's statement noted that it was prepared "at the request of lawyers acting for Dmitry Firtash ('DF'), for use in legal proceedings in Austria.

Prior to that meeting, Barr had been briefed in detail on the initial Trump-Ukraine scandal whistleblower complaint within the CIA that had been forwarded to the Justice Department, as well as on Giuliani's activities in Ukraine.

[49][44] In October 2019, Lev Parnas, a businessman who was working for diGenova and Toensing's firm as an interpreter in the Firtash case, was one of two men arrested at Dulles International Airport and accused by federal prosecutors of funneling foreign money into U.S.

The group, according to Bondy, was convened by Giuliani, Trump's personal attorney, and included Parnas, his business associate Igor Fruman, as well as journalist John Solomon and Toensing and diGenova.

[13] On April 28, 2021, federal agents executed a search warrant related to the Justice Department's ongoing criminal probe into Giuliani's pro-Trump political activities in Ukraine, at the home of Toensing, taking her cell phone.