So it seems that Nate Silver likes playing with the 270towin.com maps too.
Nate also projects what it would look like if American women for the most part refuse to vote for Trump: the whole map turns Blue (don't forget kids, there are more women voters than men voters).
As of right now, a Trump vs. Clinton matchup has Trump losing on average with about 36 to 38 percent of the Popular vote. Granted, anything can happen between now and November, but Hillary is pretty much stomping on the Donald to the tune of double-digits (much in the way Trump has been stomping on his GOP rivals in the primaries).
I've adjusted this RealClearPolitics chart that uses demographics to measure the Electoral results (based on 2012 models), and it gives a projected result where I drop the Republican support among Whites down to 49 percent (where Trump's White Male support is leveling at the moment), I drop voter turnout as likely for Whites overall (and for Blacks overall due to voter suppression efforts), I drop Hispanic support for Republicans down to 17 percent (matching the overall disgust Hispanics have for Trump right about now) and picking up their voter turnout due to increased voter participation again due to Trump's outrageous anti-Hispanic crap.
In terms of the Presidential election, the Republicans are screwed: they get only eight states, they LOSE key Red States like Arizona, Georgia, Missouri, Indiana, Ohio, Virginia, Florida, Georgia, even SOUTH CAROLINA, MISSISSIPPI and TEXAS (!). And in my humble opinion, this map is still wrong because it has Utah projected for Trump: given the Mormon distaste for Trump's bigotry, I guarantee (well, to 90 percent) that state goes Blue if Trump is the GOP candidate.
In this situation, the main question isn't how bad the Presidential loss is going to be, the question is "how bad is this going to affect the rest of the Republicans' federal elections, in the House and the Senate?"
There's no firm evidence of "the coat-tails" effect that was attributed to Ronald Reagan back in the 1980s, but there's enough correlation involving turnout to give people worried thoughts. The House is likely protected from flipping due to the extreme gerrymandering that districts undergo, and it's difficult to project due to modeling turnout per specific populations. The Senate races however, as state-wide races unprotected by skewed maps, are vulnerable to how the Presidential vote turnouts go.
I would consider Alaska staying Red in spite of Trump for the Senate, and I'd probably trade off Utah for South Carolina. Kentucky map stay Light Red if Raul Paul keeps his fanbase. My projected Senate race map based off Trump's negative effect on the GOP would look like this:
Even without the Light Blue - the slim odds states that may barely flip away from Republicans to Democrats - the Democrats get 16 extra seats to the 35 not up for election for a total of 51 seats (plus the Indy Senator Bernie for 52). That's control of the Senate, taken from the GOP. Throw in those Light Blue seat and Democratic control bumps up to 62 total seats, more than enough to shut down any Cloture threats. No more log-jamming the Senate.
Here's the very big reason why the Republican Establishment is sh-tting bricks with Trump as their nominee. His negative value to large demographics - not just Hispanics and Blacks, but educated Whites and Women - can well affect the down-ticket races especially for the Senate. If the Senate flips this bad, there's a small chance the House does too. And that gives Hillary an agreeable Congress that can give her most of her agenda.
Granted I'm not an expert on polling, and my guess is as good as anyone's (except Nate's), but it stands to reason that people angry to vote against Trump is likely to vote against the party he stands with, and the Republicans can well lose across the board if Trump is only getting below 40 percent of the national voter turnout. The vote for the Senate seats may well also be affected by how the public views the GOP's refusal to even meet with Obama's SCOTUS nominee Garland, so there's that factor but I digress...
Now I can see - somewhat - the logic behind the party Establishment's half-baked idea to run an anti-Trump third party candidate. It's not to stop Trump: it's to try and get enough Republicans to show up to vote for the rest of the ballot.