Actually that's precisely why Kerry's is worse. The purpose of the Logan Act is to prevent unauthorized people with no authority from negotiating on behalf of the United States and undermining its foreign policy. Flynn was just a few weeks from being authorized, and such authorization was certain. He just spoke too soon. Kerry is actively trying to get a foreign power to blow off the Administration that's going to be in power for at least the next 2 years and maybe longer. At least in terms of violating the intent of the Logan Act, Kerry's acts are worse. As a practical matter, will either be prosecuted? No chance in hell. The Logan Act is a joke - hasn't been enforced in literally centuries.
But he wasn't authorized and directly contradicted the current administration. Unless a POTUS term ends in November of their final year rather than Jan then he wasn't authorized. Kerry has the power of Henry Kissinger albeit less effective and eloquent. Only conservatives believe that Kerry was negotiating "on behalf of the US". None-the-less, this moral equivalence is rather self serving. Truly, either they are both wrong or both right, there is no middle ground.
But that's precisely the point. The absence of authority makes it worse, not better. They are both wrong, but that doesn't make them equivalent in severity.
