As Rudy Giuliani enters the center ring of the legal fight between President Donald Trump and special counsel Robert Mueller, the former New York City mayor is already anticipating one possible battle – a subpoena for President Trump to testify. “I think it's 50/50,” Giuliani, the president's personal attorney, told ABC News regarding the possibility of a subpoena. “But I got to prepare for that 50 percent.”

As ABC News confirmed earlier this week, the president’s legal team was told by Mueller he could “compel” the president to testify before a grand jury via a subpoena. As Ty Cobb steps down from his position as White House counsel handling the Russia probe for the presidency, his replacement, Emmet Flood, has been through battles like this before. “I think Emmet was brought in because he represented Clinton during their subpoena battle and knows a great deal about it,” Giuliani said.

Giuliani already believes he’s settled one case. The mayor argues that with the information now out about how the president reimbursed Michael Cohen for his payments to porn star Stormy Daniels, that case no longer has implications that campaign finance laws were violated.

“I think the investigation with him [Cohen] largely fell apart, with the loss of the campaign finance possible violation which never existed in the first place, but they sure thought it did,” Giuliani told ABC News Thursday night in a phone interview, adding that his client, President Trump, has nothing to worry about in this matter.

“We don't hear anything, see anything, see any documents that contradict what we've said. Some of the recollection is a little hazy because it came during a very busy period. But, I mean, on both sides it's pretty clear. They may have a little differences here and there but nothing important.” Cohen faces a criminal investigation by New York’s Southern District U.S. Attorney’s office and a civil suit from Daniels in California.

It was just on Wednesday that Giuliani revealed during a live interview with Fox News that the president repaid Cohen for the $130,000 he paid Daniels just days before the 2016 election. Questions have mounted for months to the president and the White House about what information if any Trump knew about the payment. The president declared on Air Force One earlier this year he had no knowledge of the payment.

Giuliani’s main focus remains representing the president in the special counsel’s ongoing probe of Russia collusion during the 2016 presidential election.

Giuliani will continue negotiations alongside the president’s legal team of Jay Sekulow joined by former federal prosecutors Jane and Marty Raskin, about a potential interview with the special counsel. As he’s previously indicated, the mayor wants no more than three hours of interview time. “They’re going to close the investigation within a month on and a half or two months of the interview. We’ll get all the questions in advance, we’ll knock it down to about half of what they wanted to ask.”