I think it's becoming evident with each passing day that Bernie Sanders is looking set to become the next Democratic candidate for the Oval Office. In a similar fashion to what occurred in the aftermath of the other endorsement he received recently, I see him moving-up in the opinion polls and eventually toppling Hillary Clinton.
The Nation magazine is particularly popular, and influential, among the very people who will be voting in the primaries. The endorsement will not hold much sway in the general election, should Bernie win the nomination, but in terms of the Democratic primaries, this should give him a boost among progressive activists.
I really do not think an endorsement with Nation Magazine will help Bernie Sanders win the election. I do not think that people really care about that at all. I do think that people are not going to pick Bernie because they will choose Hilary just because she is a woman. I do not think people really look too closely at the actual issues anymore.
Endorsements don't matter like they used to. This is because in the media-heavy modern world of constant news, people are forming their own opinions of politicians long before reading of anyone's endorsement. Perhaps 20 years ago major endorsements were a big deal, but I don't think they matter unless they are coming from a candidate that is dropping out and asking their followers to vote for someone else.