So why did Trump go all out to get dirt on Biden? Why not BS or Warren?

[caraher]

11. I don't think Trump's possible calculation should drive our decision

I understand the argument here but it is pure speculation regarding Trump's motives. Even if Trump prefers to run against Biden rather than Sanders or Warren that doesn't mean that Biden is the best candidate to beat Trump. Trump could actually be mistaken (imagine that!).

My own calculation is that we win this election through turnout. I see much more enthusiasm and motivation in our left wing. I honestly cannot see what is supposed to excite me about voting for Biden over any of the top-tier/middle-tier candidates beyond a fuzzy nostalgia for the Obama years.

I'm not swayed by polling a year of the head of the election that shows Biden doing better against Trump than other Dems. There's a long campaign ahead. The only poll that matters is in November of next year. To give a sense of why (and this is just the first poll from my Google search of November 2015 poll results) here is an alternate history of the last election:

One year before Election Day 2016, Dr. Ben Carson is virtually tied with Donald Trump as strong front-runners for the Republican nomination, and Carson tops former Secretary of State Hillary Clinton 50 - 40 percent in the final face-off, according to a Quinnipiac University National poll released today.

I also find the "unicorn riding over the rainbow" line pretty insulting. I'm pragmatic enough to realize that, for instance, neither Sanders nor Warren will be able to implement the policies they are campaigning on by the stroke of a pen. (And based on what we've seen with Obamacare, a program whose roots lie in right-wing politics, there's a huge chance that significant reforms will be bottled up for years in the courts Trump is packing, even if we somehow win the Senate and Presidency.) There are certainly Warren and Sanders supporters with a poor understanding of how hard it is to make big transformations, but many of us are realists.