As I show in my book, the strategy designed by the Clinton team was based on the idea they could tap into the anti-Trump sentiment among Indies (and maybe even some Rs) so long as she selected a digestible running mate (Kaine) & minimized issues in the general. It failed utterly.
Trump was right to say that Sanders as her running mate would have been a problem for him. It would have increased turnout of millennials and gen z voters & decreased defection to 3rd party voters, which was astronomically high that cycle. BC keep in mind, the goal of wooing Is
by going w the bland, centrist pick did nothing to help Clinton among Indies. She lost them in nearly every swing state anyway. In other words, she gained nothing, and paid a price for her sheepish strategy, one that @HardballChris would 100% recommend bc he is living in the 90s. 
No, something to keep in mind about 2020 versus 2016. The Ds have an advantage with Is (remember, pure Is are the only real swing voters, and we're talking 10% in each state, on average) bc these people are "change" voters. They are "generally" lower info low knowledge lower
interest voters who are constantly unhappy w the status quo and keen to break in favor of the out-party which is now Ds. When we look at the 30% of the Obama to Trump voters who say they are not voting for Trump now, these are your people. At the end of the day, WI, MI, AZ, TX
wherever, what determines if it breaks R or D will be the composition of the voters that show up (demos) bc that will determine the ultimate party breakdown of the contest (% R vs % D of the electorate). You'll understand this better after the voter file analysis comes out.
