By David Thomas
(Reuters) - A law firm representing Republican President Donald Trump's campaign in challenging U.S. election results in Pennsylvania has withdrawn from at least one of the cases contesting ballots in the battleground state.
Democrat Joe Biden captured the presidency on Saturday, thanks in part to a win in Pennsylvania. Trump has refused to concede and has repeatedly claimed, without evidence, that there was widespread voter fraud.
In a court filing on Thursday, lawyers at Porter Wright Morris & Arthur said it had agreed that its clients - the campaign and two registered voters - "will be best served if Porter Wright withdraws."
The campaign is in the process of retaining new counsel, Porter Wright said in the filing to U.S. District Judge Matthew Brann in Williamsport, Pennsylvania.
The lawsuit, filed on Sunday in federal court in Pennslyvania, alleges that the state's mail-in voting system "lacked all of the hallmarks of transparency and verifiability that were present for in-person voters."
"We’ve committed to the court to fulfill our obligations as required to ensure transition to substitute counsel, and so as not to cause material adverse effect on the client’s interest. We will have no further comment," Porter Wright said in a statement.
A Trump campaign spokeswoman did not immediately respond to a request for comment.
Facing criticism over its work for the campaign from some Democrats and The Lincoln Project, a group of anti-Trump Republicans, Porter Wright said on Wednesday that it has a "long history" of bipartisan election work which "calls for us to take on controversial cases."
The Trump campaign has filed a flurry of lawsuits, part of a larger strategy to try to overturn the election results in key states.
Porter Wright's withdrawal came after Jones Day, the Trump campaign's outside counsel, said on Tuesday it is not representing the president or his campaign in "any litigation alleging voter fraud" or litigation seeking to overturn the U.S. election.
Another firm, Snell & Wilmer, withdrew on Tuesday from a lawsuit alleging that Arizona's Maricopa County incorrectly rejected some votes cast on Election Day on Nov. 3. The firm said it does not comment on client matters.
(Reporting by David Thomas; Editing by David Bario, Noeleen Walder and Jonathan Oatis)