But the President has issued several pardons in recent weeks, which some have interpreted as a signal to affiliates being targeted by Mueller's probe not to cooperate with the investigation.
Even members of the President's own party have urged him to stop talking about pardons.
"I think it would be more helpful if the President never mentioned the word 'pardon' again with respect to the investigation," Senator Susan Collins, (R), said on CBS' Face the Nation.
Giuliani pushed back on the notion that in discussing his pardon power, the President had been suggesting doing anything untoward.
"You're not going to get a pardon just because you're involved in this investigation - you probably have a higher burden if you're involved in this investigation compared to the others who get pardoned," he said.
"But you're certainly not excluded from it if the President and his advisers, not me, come to the conclusion that you've been treated unfairly."
Giuliani said he would not be advising Trump on pardons, noting, "I shouldn't be involved in that process because I'm probably too rooted in his defence."
But he did accuse the Mueller investigation - yet again - of being "political" and rife with "unfairness," perhaps unfair enough to merit pardons for those who get caught by it.
"Going back to Nixon, Ford ... even Bush and Clinton ... these pardons happened in these political investigations," Giuliani said. "That mean they're going to happen here, doesn't mean anyone should rely on it.
"But there is a lot of unfairness out there," he continued. "We don't know the full scope of it."
The President weighed in on Twitter with his opinion of the Mueller probe, again calling it a "WITCH HUNT!" and declaring that law enforcement officials had a "Double Standard!" in their investigations of him and Hillary Clinton.
"There was no Russian Collusion. Oh, I see, there was no Russian Collusion, so now they look for obstruction on the no Russian Collusion," Trump wrote. "The phony Russian Collusion was a made up Hoax. Too bad they didn't look at Crooked Hillary like this."
Trump has not yet spoken to Mueller as part of the probe, and Giuliani suggested that he should not do so under oath - pointing to Trump's recent backpedalling on how he characterised his son Donald Trump jnr's 2016 meeting with a Russian lawyer as evidence of why it's hard to sort out "a lot of different recollections."
"That's why you don't want to go under oath," Giuliani said.