"If Hillary [Clinton] were to win 54-46, oh my God. It’s all over. If it's 53-47, and I think that’s in the realm of possibility ... that’s a big deal. Five or more [percentage points] is a big deal."
According to political prognosticators, she's right. If Clinton could get 54 percent* of the vote in November, said Kyle Kondik and Geoffrey Skelley of the University of Virginia's Center for Politics, it would provide a wave big enough for down-ballot Democrats to surf to victory in enough races to give House Democrats the majority.
(*For the purpose of determining which party controls congressional seats, we and the University of Virginia are measuring all vote totals as between the two major parties. So among Democratic and Republican voters, President Obama got almost 52 percent of the vote, and Clinton would have to get 54 percent of the two-party vote. The number changes when you add in non-major-party voters, such as independents, etc.)
Implicit in this calculation is the assumption that when people go to the polls to vote for president, most of them are going to vote for that same party all the way down the ballot. There's evidence that we'll see that happen in November, because split-ticket voting is the lowest it has been in 50 years.
If enough people vote for Clinton, enough House Democrats will be elevated to victory, too.
If Clinton wins by eight points, to hang on to their seats — and their majority — House Republicans would have to outperform Trump in their districts by about eight to 10 points. That's very hard to do.
For one thing, House races don't tend to be the races to which the average voter pays close attention. Also, as GOP pollster Robert Blizzard pointed out recently (and The Fix's Chris Cillizza expanded on), in 2012, the average GOP candidate in a competitive race outperformed Mitt Romney by just a single point.
So a Democratic takeover is possible. That, of course, doesn't mean it's easy.
They have to run the table on competitive districts, winning about two dozen of the 40 or so competitive Republican-held seats and holding on to a majority of their 11 competitive seats (for a net 30-seat gain. Republicans currently control 247 seats.).
Clinton could help them do that by routing Trump — but she'd have to run not only the race of her life, but the best race a Democrat, or anyone else, has run in many, many years. A 54 percent showing would be the highest percentage a winning presidential candidate has received in two decades. (Obama got 52 percent of the vote in 2012, and his 2008 win got him 53.7 percent of the vote.)
Earlier in the summer, Clinton looked as though she was on pace to at least reach for 54. She had a double-digit lead in a late June Washington Post-ABC news poll as the bottom fell out from under Trump amid some of his self-inflicted wounds.
To sum up, partisanship is working both ways for House Democrats. In a wave election for Clinton, the lack of split-ticket voting could help them reach a goal we once called "far-fetched." On the flip side, we're also seeing evidence that Americans aren't quite willing to give Clinton such a big win, even against the least-liked major-party candidate in modern times.
But the main point is to correct the record here on The Fix: Given current conditions, Pelosi was right. Depending on how well Clinton performs in November, Democrats do have a shot at taking back the House.