don't think I understand the advantage of declaring a single term intention. Wouldn't that make him a lame duck after two-ish years?

If he gets elected and is in great health leading up to a 2nd term then we need him to serve a 2nd term. If he's not feeling healthy enough to serve a 2nd term I don't believe he would.

I'm sure that he would/will select a fantastic V.P. candidate if anything happened to him that would make a great President.

His job and obligation would be to choose a strong V.P. in case anything happens to him (as all Presidents must do). He won't be choosing Sarah Palin that's for sure.

He can make the determination June 2019 or so whether he'll have the energy and health for another 4 years.

"I'm announcing that I intend to be a lame duck if elected. Please sharpen your swords, I'll be putting my neck on the block now."

No.

... and that way he can say that so many women who are looking heavily towards Hillary Clinton as a means to have a woman in the White House as a higher priority than her policies, will perhaps see that he's committed to trying to get that to happen as early as possible by putting Warren in the prime position of being able to take over in 2020 then. Then committing to a single term might make sense, as Warren might not want to wait for 8 years to run for president.

And if she commits to following through on many of his agenda items, then we'd all be voting for a movement, and not just a single person, and having such a commitment would show that this movement is committed to getting everyone to feel a part of it by having a woman being a likely leader in 2020 with the same agenda of restoring the middle class and disempowering the 1% that has been needed for such a long time now too.

To step down with no one to take his place that carries on the mission in my book, and many supporters of his is not useful.

FDR certainly took longer than a four year term to carry through on rebuilding the country when it was needed then. He had a few missteps on the way that he overcame later too.

If he were to step down to let Warren take charge in 2020, it could still be viewed potentially as a 12 year project then if Warren stays there for two terms, and potentially who she takes as a running mate later hopefully also carrying on his tradition.

He is a bit old perhaps for two terms, but that's still not necessarily a problem. But additionally by having someone like Warren inline for the presidency, it helps perhaps bring many in the Clinton camp wanting a woman president and his camp together for the general election.

Committing to a single term without being clear on who would follow him as VP in my book doesn't work to drum up a revolutionary movement to elect him.

get what he wanted done. He also said that is why our presidents now often have so much trouble turning the country around. Especially if they only have 4 years.

He needs strong legislative leaders to promote his agenda.

Besides Warren, there are plenty of leaders in the progressive caucus - for example Elijah Cummings.

... to protect him from those who might want to try and out a populist if they feel the VP will answer to big money better, in addition to inheriting the task with the same viewpoints and mission that likely might even last more than two terms like it did for FDR to put some huge reformational changes in place. So that would be one requirement. Elizabeth Warren as a woman candidate would also help bring on board former Hillary campaign followers if he were to win the nomination who are feeling very strongly that the U.S. can finally elect a woman who represents half our population but who has never had direct representation for president. I think that drives a lot of those who back the Clinton campaign. By saying that a woman could be first in line to take over in 2020 if he were to step down after one term would be that much more of a drawing card for them to come out and vote for him and not stay home. Perhaps other women can fit this bill too, but Warren seem the best option at this time.

We already have what you might call term limits. They are called elections. Besides, with all the things that Bernie wants to do, he will probably need more than four years.

(Doesn't everything?) The Iowa caucus starts near the end of January. That is not a heck of a lot of time. If he we to announce this, everyone who interviews him is going to start asking about it. That takes him off message.

That said, I am not in charge of his campaign. You could always call his campaign and suggest it.