The Atlantic may not be an important shaper of opinion among Democrats but this piece is the most convincing of several I've read saying that a major problem for Democrats in 2016 was a perceived lack of conviction caused by listening too much to the Third Way, a group heavily supported by Wall Street interests and country club Democrats, which has counseled Democrats to support a "centrist" way, even asking Democrats to be open to cutting Social Security. While Hillary Clinton does have convictions, she didn't campaign that way. Neither did most other Democratic candidates apart from Bernie Sanders. For his part, Trump projected conviction even though he seems to have no true convictions unless you count greed and arrogance. There are strong signs that Democratic candidates are eager to avoid repeating the mistake of standing for little.
I write about this because aggressively supporting increases in Social Security benefits would be an excellent way for Democrats to show conviction in 2018. Whether they make it a centerpiece of their 2018 campaign or not, it's clear that if Democrats win in 2018, there's going to be a dramatically different atmosphere in Washington and that will affect Social Security. If nothing else, Democratic leaders won't be suggesting any openness to Social Security "reform" in the foreseeable future. If you support that, you're not a Democrat. The Third Way may have money but it doesn't have votes and, in the end, votes are what matter.