Donald Trump, who's currently running eight points behind Hillary Clinton nationally, may just prove enough of a drag on GOP candidates yet to deliver the House to Democrats. That's the surprisingly insightful conclusion Chris Cillizza drew from a telling tweet storm by GOP pollster Robert Blizzard of Public Opinion Strategies.
Blizzard's main insight after studying Mitt Romney's effect on 2012 House races: At best, Republican candidates can generally run "about 5 points higher than Trump, give or take a few, depending on the district/candidate." That means that if Trump is running below 45 percent in any given Congressional district (and he’s currently running at 40 percent nationally), it would be an uphill climb for the GOP candidate there to win based solely on Trump's unpopularity. In other words, the ability of these GOP candidates to separate themselves from the top of the ticket has limitations—typically in the 5-point region.
Cillizza then focused on 45 Republican seats deemed competitive by the Cook Political Report (11 Democratic seats are also competitive, but they'll likely be safe in the event of a wave election). The districts of 40 of those GOP seats are essentially the same as they were in 2012. Using the Cook Report's Partisan Voting Index (PVI) to gauge how those 40 districts compared to the presidential race in 2012, he found 36 seats had a PVI of R +5 or lower—meaning those GOP candidates likely wouldn't be able to outperform Trump by enough of a margin to hold their seat if Trump is tanking in their district.
If Republicans lost all 36 of those seats with a PVI of R +5 or lower — and Democrats held all 11 of their contested seats — Democrats have the House majority. By six seats. Twenty-seven of those 40 seats have a PVI of R+3 or lower. Win those 27 and Democrats need to pick up only three seats among the slightly more Republican-friendly districts to win the majority. [...]
If you trust Blizzard's calculations — and I do — it suggests that if the bottom drops out on Trump, which appears to be happening as I type, there are a good number of Republican-held House districts that could suddenly collapse with him.
All of which means that if Republicans think they have hit rock bottom, they may need to wait only a few months to find an even lower floor.
Just wow.