Mueller, the special counsel appointed to investigate crimes associated with Russia's alleged interference in the 2016 election in the US, hasn't yet made a formal request, and no date has been set, but Bob Driscoll, former deputy assistant attorney general for the Civil Rights Division at the US Department of Justice, told Radio Sputnik's Fault Lines that he believes Mueller will "at least ask," adding that then it will be for Trump's lawyers to "negotiate the kind of least intrusive means to do it."
According to Driscoll, the authority of the special counsel will likely be challenged when faced with the authority of a sitting president, and Trump's lawyers will probably try to set ground rules for any interview or limit it to providing answers to written questions.
"There could be all kinds of limitations they can put on, and so I suspect that is what they'll do," Driscoll said. "Mueller doesn't want [the investigation] to drag on, I suspect, for another couple of years, which is what it would do if there's a full scale assault on his authority. It would obviously take time in the courts."
"With special counsel you generally pick the person first and then have the prosecutor look for the crime, which is generally not the way our system works," Driscoll added. "Usually the prosecutors are out there looking for crimes, and when they identify crimes they identify the people that commit them."
One frequent problem is that special counsel investigations end up having people prosecuted for crimes that have nothing to do with their initial inquiry, as when former US President Bill Clinton was impeached over transgressions "totally unrelated" to the Whitewater real estate transaction controversy that was its initial basis.
"Similarly, so far in [Trump's] case, now we have indictments based on lobbying activities and other things that are years if not decades before Trump ever ran for president," Driscoll said.
A number of senior Russian officials, including Russian President Vladimir Putin, have more than once denied the "groundless" allegations that Moscow attempted to influence the 2016 presidential election, pointing out that little evidence to support the claims has been provided.
Trump has repeatedly rejected allegations of collusion with Moscow, describing Mueller's probe as a "witch hunt."