I don't think Clinton would have been very successful at getting effective policy passed. I think she would have been similar to but slightly worse than Obama's administration because they're bought by the same donors. The best thing she had to offer was "Well, at least it's not a Republican..", meaning things like the EPA, and PP most likely wouldn't have been touched and there wouldn't be any Muslim ban. But things like campaign finance reform, single payer healthcare, infrastructure spending, etc. wouldn't have been priorities.
Sanders would have shamed both establishment Democrats and Republicans into supporting his policies because he knew he had the majority of American support on his side. We've been over the facts dozens of times, healthcare, college, foreign policy, LGBT rights, etc., on virtually every issue he has support from the majority of the American people, conservative and liberal. So you get someone like Joe Manchin voting against effective climate change policy, Sanders goes to West Virginia and has a talk with Joe about how if he doesn't get onboard, he will use all of the resources available to him to primary him in his next senate race and support his opponent. When Sanders would give interviews to the media, he would name all the Democratic congressmen who oppose his policy, then bring up how much of their political contributions came from the oil & gas industry. Either Manchin and other establishment Democrats roll over or they won't be Democratic politicians much longer. You do the same thing with Republicans.
You force it through with strong leadership from the top with a specific goal and constant political pressure from the bottom, from voters doing exactly what they've been doing protesting Trump, showing up to town halls and calling these politicians out on their lies to their face. If Sanders is out there every single day like he was during the campaign and like he still is today even though he's not running for anything, talking policy and putting political pressure on politicians who vote against the American people's interest, the American people will hear him and listen to him and all of these empty suits would have no way to defend against it.
