Bill McKibben is more like Hillary Clinton than you realize.

Bill McKibben

"I periodically remind myself of what President Franklin D. Roosevelt told labor leaders who urged him to enact progressive legislation after his 1932 election: 'I agree with you. I want to do it; now, make me do it.'” --Henry Weinstein

A POTUS represents about 320M people.  They cannot stray too far afield of what they perceive are the goals and interests of those 320M people.  In fact, it is their OBLIGATION not to stray too far.

All leaders must look to their constituencies to define the boundaries of what they can and should accomplish.  Sometimes this is frustrating.  In climate change, we want them to end oil, coal and gas, now...as in yesterday now.  But in asking them to do that, we must recognize the limits are not what they stand for.  The limits are in what we stand for.

This is true even among those that we hold as most principled.  Bill McKibben is a fierce climate activist.  His dedication to cutting carbon emissions cannot be in doubt.  Savvy, capable, driven, principled and fully committed.  However, like any leader, he is answerable to his constituency.  (He doesn't have the same constituency as a POTUS, of course.  His is made up of climate activists.)  He is answerable to that constituency, even to the point of having a different public stance from his private one:

"After McKibben gave his rousing speech to an enthusiastic audience, I was able to grab him for a moment in back of the little makeshift stage. I asked him about nuclear power. He admitted that nuclear was going to be necessary if we were ever to reduce the amount of carbon in the atmosphere. “Why don’t you come out favorably in public for nuclear power, then?” I asked. He surveyed the hillside, almost half the people crusading against Vermont Yankee. “If I came out in favor of nuclear,” he said, “it would split this movement in half.”

So there you have it. McKibben, like many other environmentalists, knows in his heart that there isn’t much chance of reducing carbon output without nuclear. But he does not want to be caught saying so in public."   http://www.realclearenergy.org/articles/2015/11/12/how_about_suing_bill_mckibben_for_racketeering_108880.html

Here is our reality.  We must move almost 320M Americans to stop using fossil fuels.  We must move 7.4B human beings across the globe.

We don't all agree on things.  We don't all share the same values.  This is not easy.  This is HARD.

And our leaders can only lead us where we will follow.  That is not their failure or success.  It is ours.