When talking about an upcoming election, a friend often asks, “Charlie, if you are wrong, how are you wrong?” I’ve always found that to be a good intellectual exercise for anyone in the prognostication business and, frankly, in a lot of other professions as well.

Today there certainly appears to be a Democratic wave building for this midterm election. Over the past 13 months, election results have pointed toward a wave; the GOP is 0-for-5 in statewide elections, and have, after results in Missouri this week and Wisconsin last month, lost 35 state-legislative seats to Democrats while only gaining four previously Democratic seats. While Republicans have not lost any special congressional elections yet, their performances have significantly trailed previous GOP numbers in those districts.

President Trump’s job-approval ratings have ticked up a couple of points to 40 percent, but that is still by far the lowest of any president a year into his first term and 10 points short of the number where past White House occupants have managed to prevent midterm-election losses. The Democratic advantage in national generic-ballot test polls is still at about a half-dozen points, half of where it was a couple of months ago but still very much in danger territory for the GOP.

Private polling from both parties shows some pretty grisly numbers in individual states and districts. Democratic candidate recruiting in House races is going spectacularly well—in fact, some worry it’s gone too well, with too many contested primaries. Fundraising for Democratic challengers is going very well (and you should ignore Democratic National Committee and Republican National Committee fundraising numbers, which are some of the most irrelevant midterm indicators in all of American politics). All of these signs support the very clear historic pattern of midterm-election losses for the party in power.

A disclaimer is necessary at this point: The election is 271 days away, so things can certainly change, but that is precisely the point—things would have to change for the GOP to hang on to their majority. As of now, I’d put the odds of Democrats winning a House majority at about 60 percent, and winning the Senate a much lower 25 to 35 percent. Jennifer Duffy, The Cook Political Report’s senior editor and specialist in Senate and gubernatorial races, believes that if Democrats don’t have a net gain of four or five governorships, they will have had a bad night, while anything more than eight would be a great night for Democrats. While the Senate, with its six-year terms, has a map that heavily favors Republicans because Democrats did so well in 2006 and 2012, the gubernatorial map works against Republicans who had great 2010 and 2014 elections (all but New Hampshire and Vermont have four-year terms).

So short of a seismic event like another 9/11, what could deter a Democratic wave? I keep coming back to the economy: Does the economy continue to grow and at some point, might Trump begin to get more credit for that than he does now? Does he become less of a liability for Republicans?

Almost a month ago, a Gallup poll (taken Jan. 8-14) found that while 56 percent of Americans gave President Obama “a great deal” or a “moderate amount” of credit for this past year’s economic improvement, only 49 percent gave Trump similar credit. A newer Quinnipiac University poll (Feb. 2-5) found that 70 percent rated the state of the nation’s economy as either excellent or good, up from 66 percent in January, 63 percent in December, and 58 percent in November. When asked whom they believe to be more responsible for the current state of the economy, 48 percent chose Trump, and 41 percent said Obama. The two were tied on this question in last month’s poll.

I know as well as anyone the dangers in comparing results from nonidentical questions asked by different pollsters and, to be honest, have never been the biggest fan of Quinnipiac’s polling, but I do believe that this is an important dynamic to watch in the coming months. It should be added that in this Quinnipiac poll, even with this increased optimism about the economy and more credit given to Trump—and his job rating ticking up to 40 percent—the Republican Party’s favorable ratings were still minus-19 points (32 percent favorable, 51 percent unfavorable), compared to minus-12 for Democrats (35 percent favorable, 47 percent unfavorable). By a 9-point margin, 49 to 40 percent, Americans preferred Democrats to control the House.

In short, the view of the economy is up, and Trump’s numbers are up a bit, but the GOP is still in trouble. For now, the wave still appears to be coming.

This story was originally published on nationaljournal.com on February 9, 2018