"At the end of the day, what is most important to me is to see Donald Trump not being re-elected president, and I intend to do everything I can to make sure it doesn't.
" But if – and this is one if – if next year, a year and a half, go directly into the heart of the election, it is all that Congress is talking about threatening Trump and Trump, Trump, Trump and Mueller, Mueller, Mueller, and we Don't talk about healthcare, we're not talking about raising the minimum wage to a living wage, we're not talking about fighting climate change, we're not talking about sexism and racism and homophobia, and all issues that concern ordinary Americans, what I'm worried about are it that works for Trump's advantage. "
Sanders went on to say that he supports the chamber which is conducting an investigation of some of the apparently obstructive behaviors of Trump documented by Mueller and that when an investigation concluded he was open to review. [1
2) Impeachment allows Trump to paint as a victim for exaggerated partisan democrats who want to run him out because they lost a choice.  Senate Republicans will simply not abandon Trump a mass which ensures that even if persecution succeeds in the House, Trump will not be removed from the office.
Considering the three competing realities, Sander's position – we must continue to investigate, but we cannot build the whole D Emocratic case against Trump 2020 on impeachment – is the most politically sound place to be.
Although Sanders did not mention the 2016 campaign or Hillary Clinton's strategy against Trump in that competition, it is obvious that his position on Trump and impeachment is informed by that competition.
2016 Clinton Underlying (and sometimes overlying) message was something like this: Trump is horrible and you will never vote for him. And I'm the only other person running for president.
In short, the 2016 competition became a personality competition between two people that the voters did not like. So they chose the one you thought could change things more.
Sanders is clearly cautious – and rightly so – about resuming that competition. To that point, this part of his impeachment response really hit a chord:
" I f for next year, a year and a half, goes directly into the heart of the election, all that the Congress talks about is impeaching Trump and Trump, Trump, Trump and Mueller, Mueller, Mueller, and we are not talking about the care, we are not talking about raising the minimum wage to a living wage, not talking about combating climate change, we are not talking about sexism and racism and homophobia, and all issues related to ordinary Americans, what I worry about is that it works for Trump's advantage. "
That's a proper assessment. Democrats do not have to convince voters that Donald Trump is not president or not their cup of tea. Most – in addition to Trump's hard-defense – already believe it. What democrats need to do is show voters that Trump's policy is dangerous on the issues they care about. Whether it's his call to repeal the Affordable Care Act or his decision to withdraw the US from the Paris Climate Accord or his tough immigration policy.
What Sanders argues for is that the way you beat Trump is on politics, not on personality. And that if Democrats spend the next 18 months talking about whether Trump would be discouraged for his particular incredible behavior during the Mueller investigation, they allow the race to be about personalities, not politics.
Make no mistake: Sanders knows that by not demanding Trump to retaliate, he opposes the wishes of the most liberal democrats that make up his base. His decision to do so suggests that, unlike its 2016 campaign, Sanders is more focused on winning – nominating and chairing – than just proving a point.