Republicans revel in the prospect of Barrett joining the bench, where conservatives now occupy five of nine seats and her confirmation could cement the court's rightward tilt for decades.
Democrats, meanwhile, were using the hearings to remind voters that healthcare for millions is at stake and to convince them that Trump has been deeply irresponsible in his coronavirus pandemic response.
They have painted the Supreme Court nominee as a direct threat to the Affordable Care Act and voiced concern her appointment is being rammed through in time for the court to hear a challenge to the law on November 10.
'Illegitimate'
The Supreme Court hearing, forced onto the calendar even as 10 million Americans already cast ballots as of Monday, has emerged as a political flashpoint.
While Republicans praised Amy Coney Barrett as a competent nominee grounded in family values, Senate Democrat Sheldon Whitehouse summarized his party's hostility to her confirmation, calling her a "judicial torpedo" fired at the health law that protects millions of Americans.
And Democratic vice-presidential candidate Kamala Harris — speaking by videolink — slammed as "reckless" the decision to hold the hearing at all during a pandemic, with two Republican panelists among a recent outbreak of Covid-19 cases linked to the White House.
"This Supreme Court nomination process is illegitimate and deliberately defies the will of the people," she added later on Twitter, highlighting Democratic arguments that voters should decide who gets to pick Ginsburg's replacement.
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Senator Mike Lee appeared in person to deliver his remarks maskless, despite announcing his Covid-19 diagnosis 10 days earlier, prompting some to highlight the health dangers for the committee members.