Can someone explain why an incoming president needed a back channel to Moscow?

Special counsel Robert S. Mueller III has gathered evidence that a secret meeting in the Seychelles just before the inauguration of Donald Trump was an effort to establish a back-channel between the incoming administration and the Kremlin — apparently contradicting statements made to lawmakers by one of its participants, according to people familiar with the matter.

In January, 2016, Erik Prince, the founder of the private military company Blackwater, met with a Russian official close to President Vladi­mir Putin, and later described the meeting to congressional investigators as a chance encounter that was not a planned discussion of U.S.-Russia relations.

A witness cooperating with Mueller has told investigators the meeting was set up in advance so that a representative of the Trump transition could meet with an emissary from Moscow to discuss future relations between the two countries, according to the people familiar with the matter, who spoke on the condition of anonymity to discuss sensitive matters.

George Nader, a Lebanese-American business who helped organize and attended the Seychelles meeting, has testified on the matter before a grand jury gathering evidence about discussions between the Trump transition team and emissaries of the Kremlin, as part of Mueller’s investigation into Russian efforts to interfere with the 2016 election.