[1][2] MacDonough guided the Senate through the first and second impeachment trials of Donald Trump, and she and her staff brought the Electoral College certificates to safety during the January 6 Capitol attack.

"[1] Sen. John Thune (R-SD) said "she's very steeped in the traditions of the Senate and understands how it works here" and Sen. Mark Warner (D-VA) said he had "no question about her ability to read the rules and make the right decisions.

"[9] During the 2015 congressional effort to partially repeal the Patient Protection and Affordable Care Act (ACA), MacDonough ruled the provision that would roll back the Independent Payment Advisory Board disqualified the 2015 package from consideration as a reconciliation bill in the Senate under the Byrd Rule, which requires that reconciliation bills must have a budgetary effect.

"[11] In January 2017, Speaker of the House of Representatives Paul Ryan (R-WI) said that MacDonough would be the person to "watch" in the Senate, because budget reconciliation would likely again be the tool used to pass amendments to the Affordable Care Act.

[12][13] During the passage of the Tax Cuts and Jobs Act of 2017 MacDonough ruled the repeal of the Johnson Amendment, which limits the political speech of churches, could not be included in the bill.

[17][18] In a 2018 commencement speech at her alma mater, Vermont Law School, MacDonough called the invocation of the 'nuclear option' in 2013 and 2017 as a "stinging defeat that I tried not to take personally".

[21] In January 2021, MacDonough and her staff safeguarded the electoral college votes from the 2020 presidential election by removing them to a secure location as rioters breached the Capitol building.

"[27] On September 30, 2021, protesters blocked traffic on the Golden Gate Bridge for about an hour to call for a path to citizenship, with some carrying a banner urging Democrats to "overrule the parliamentarian".