Demonstrators gather outside Jones Day law firm in New York protesting its representation of Trump in election lawsuits

Protesters have gathered outside the New York offices of Jones Day, a law firm representing Donald Trump in his legal battle to have votes thrown out in an attempt to secure his reelection.

The law firm has come under fire for helping Mr Trump in a lawsuit challenging Pennsylvania's extended deadline for receiving mail-in ballots. The state's Supreme Court allowed the state to count mail-in ballots that were postmarked by 3 Nov. but arrived up to three days after the election.

Those ballots are likely to heavily favour President-elect Joe Biden.

Law students from Harvard and numerous other law schools across the US are threatening to boycott the firm, and the prominent Republican anti-Trump group, the Lincoln Project, has targeted the lawsuit online.

Jones Day defended its representation in a statement issued Tuesday. It said that the case raises important questions regarding the constitution's guidance on elections.

Critics see Jones Day as complicit in Mr Trump's attempts to undermine the American public's faith in the nation's electoral system and undermine legally cast votes.

Jones Day attempted to distance itself from Republicans' legal battle following the announcement that Mr Biden was projected to win the election on Saturday. It claimed it was not "representing any entity in any litigation challenging or contesting the results of the 2020 general election."

However, attorneys working for Jones Day reportedly feel conflicted about the firm's involvement with Mr Trump's case. The New York Times reported that sources within the company - speaking on the condition of anonymity - said attorneys were considering leaving the company over its entanglement with the Republican-led litigation.

According to data from the Federal Election Commission, Jones Day has made $20m from the Trump campaign, the RNC and pro-Trump groups it holds as clients.  

Despite its involvement, some have come to the defense of the law firm, noting that the defense of unpopular clients is a core tenant of the US legal system.

"Going after lawyers for representing unpopular clients in unpopular legal claims has a really bad history, and tends to not go well," Orin Kerr, a professor at the University of California Berkeley School of Law, said on Twitter. "Our legal system needs lawyers to take on unpopular clients."

Even still, the backlash against the law firm continues.

The Lincoln Project - headed by conservative lawyer George Conway and which spent the election season attacking Mr Trump - said it will spend $500,000 on ads targeting Jones Day and other small law firms that are working for Mr Trump.

The ads allege that Jones Day is "waging lawfare" on Mr Trump's behalf and damaging the public's trust in US elections.

Mr Conway said the ads would encourage lawyers and clients to abandon Jones Day.

In San Francisco, activists and protesters painted a huge mural outside the city's Jones Day office on Montgomery Street. The mural reads "Count Every Vote" and "Jones Day: Hands Off Our Ballots."

Several law firms have already dropped out of Mr Trump's legal battle after few of the campaign's cases have shown any promise of succeeding in the courts.

Last week, Porter Wright Morris & Arthur pulled out of a lawsuit in Pennsylvania.

Another law firm, Snell & Wilmer based in Arizona, moved to withdraw itself from an election-related case. A judge granted the firm's request on Tuesday.