Fact remains though - when the call was made he was
1) Not in any way part of the executive branch
2) Not in any way authorized to speak on behalf of the executive branch
And therefore: flagrantly undermining the foreign policy objectives of the sitting president of the united states. Which is a crime and this application of the Logan act would almost certainly pass constitutional muster.
Didn't Nancy Pelosi undermine GWB's foreign policy objective of isolating Syria when she went there in 2007?
Or the 47 republican senators who wrote to Iran in 2015.
According to a memo in 1983 from Victor Chebrikov (head of the KGB) Ted Kennedy attempted to make a deal with Yuri Andropov to help him deal with Reagan if he would help him in the 1984 election.
Henry Ford, Jane Fonda, and many others have been accused of being in violation of the Logan act. I can go on naming possible violations, but it would be silly. The Logan Act is a pointless law from over 200 years ago that no one has ever been convicted of violating. I think there has only ever been one person charged with it, but was never convicted. Hell, the guy it was named after was elected to the senate two years after it was passed into law.