On Tuesday Rudy Giuliani handled his first federal case in almost three decades as he took over the Trump campaign challenge to Joe Biden’s projected win in Pennsylvania.

On Sunday, Giuliani said he has “proof that I can’t disclose yet” about corrupt voting machines, as well as “more than enough illegal ballots already documented to overturn the result” in key swing states and secure Trump’s re-election.

The Associated Press reported that supporters of President Trump cheered Giuliani as he entered the courthouse today. Once inside Giuliani asked Judge Matthew Brann if he was formally approved to represent Trump, according to Reuters.

“You’re good to go,” Brann responded.

Records show that Giuliani hasn’t entered an appearance in federal court since 1992, the year before he was first elected mayor of New York City. Giuliani filed paperwork seeking to represent Trump on Tuesday morning, after Philadelphia election lawyer Linda Kerns and two Texas lawyers sought permission to quit the case, citing harassment and abuse from opposition lawyers and anti-trump groups.

The Trump team allege that officials in heavily Democratic counties illegally let voters “cure,” or fix, mail-in ballots that had problems making them ineligible to be counted.

That allegedly led to the “unlawful dilution or debasement” of properly cast ballots in Republican areas where officials “followed the law and did not provide a notice and cure process, disenfranchising many.”

Biden’s unofficially leads Trump by more than 73,000 votes in Pennsylvania.