The Senate parliamentarian, a critical but often low-profile arbiter of the chamber's procedural actions, is the subject of frustration from some liberals after a crucial blow to Democrats' agenda late Thursday.

Elizabeth MacDonough is the unelected, nonpartisan interpreter of chamber rules, commonly referred to as the Senate referee. She nixed a Democratic push to add a $15-an-hour federal minimum wage increase to President Biden's $1.9 trillion coronavirus relief package, dubbed the American Rescue Plan.

The reason?

She said it did not meet the strict requirements of reconciliation, a fast-track process that allows the majority party to pass big-ticket legislation with a simple 51-vote majority.

MacDonough's decision has thrust her into the spotlight, especially as some progressives have called for her decision to be ignored, and for Vice President Harris, who serves as the president of the Senate, to overrule her. Rep. Ilhan Omar, D-Minn., called for MacDonough to be replaced.

The White House issued a statement saying the president was "disappointed" in the ruling but "respects the parliamentarian's decision."

Who is Elizabeth MacDonough?

MacDonough is the first woman to serve as Senate parliamentarian. She was named to the job in 2012, when Democrats were in control of the chamber.

Her predecessor, Alan Frumin, actually held the position twice.

His second stint came about in 2001 following the Republican ouster of then-parliamentarian Robert Dove. Dove angered the GOP majority, including Majority Leader Trent Lott, for rulings that made it difficult to push President George W. Bush's budget and tax agenda through an evenly split Senate, according to The Washington Post.

MacDonough is a career civil servant who previously served as a reference assistant in the Senate Library. She studied at George Washington University, where she earned a degree in English literature. and later attended Vermont Law School, according to her profile on LinkedIn.

She briefly served as an assistant district counsel for the U.S. Justice Department before taking a position as senior assistant parliamentarian in 1999. It was a post she would hold for the 13 years, before being assuming her current role.

Refereeing Obamacare fight

The ruling against congressional Democrats' prized push to boost the federal minimum wage is not the first time MacDonough has been in the spotlight.

In a 2015 profile, Politico said, "She may very well be the most powerful person in Washington in determining how far Republicans can go in trying to repeal Obamacare."

As The Wall Street Journal recently wrote, when Republicans attempted to repeal the Affordable Care Act, they ran into issues rolling back the individual mandate portion of the law.

However, after the GOP majority conferred with MacDonough, it decided to leave the mandate intact, but ultimately reduced the penalty to $0, effectively making the penalty moot.

Bipartisan praise

MacDonough has largely been considered a steady and measured Senate presence.

In the mid-1990s, when then-Senate Majority Leader Bob Dole, R-Kan., and the chamber's then-Minority Leader Tom Daschle, D-S.D., both praised MacDonough before she left for law school.

"The Senate will lose one of its most dedicated floor staffers today," Dole said, according to an Aug. 5, 1995, congressional record.

"In addition to her duties preparing the morning business section of the RECORD, Liz can be found sitting at the corner of the Reporters' table in the well of the Senate, listening intently to our every word, ready to chase us down to retrieve those materials we have asked to have printed in the RECORD. We will miss her dedication and wonderful sense of humor," Dole said.

Daschle added: "She has been a delight to work with. We wish her well as she goes on to school and hope that she comes back frequently. She has been a very, very important member of the floor staff, and we are delighted to have had the opportunity to work with her."

NPR's Jane Gilvin and Mary Glendinning contributed research for this report.

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