Some election watchers treat independent voters like the golden key to open up Star World in “Super Mario World.” If you know who is winning independents, the thinking goes, then you know who is going to win the election. There’s an appealing simplicity to the logic of this: If Democrats vote for the Democrat and Republicans vote for the Republican, then whoever wins independents wins. The problem: It just isn’t true historically, and it may be wrong this election, as well. Donald Trump is currently winning independent voters and is still trailing Hillary Clinton in the polls.

Clinton leads Trump by 3 percentage points in an average of live-interview telephone polls conducted over the last three weeks. In the same nine polls, Trump is carrying independent voters by an average of 7 points.

CLINTON’S MARGIN POLLSTER OVERALL AMONG INDEPENDENTS DIFFERENCE ABC News/Washington Post +5 +2 -3 CNN/ORC -2 -20 -18 Fox News +2 -12 -14 GWU Battleground +2 -12 -14 IBD/TIPP 0 -9 -9 Monmouth U. +7 +5 -2 Quinnipiac U. +2 -9 -11 RKM Research +3 -15 -18 Suffolk U. +7 +4 -3 Average +3 -7 -10 Clinton is losing independent voters Average of live-interview telephone polls conducted over the three weeks preceding Sept. 14.

Although the results differ from poll to poll, a clear pattern emerges: Trump does better with independents than he does with the electorate at large. Clinton is still winning overall because she is doing better with Democrats than Trump is with Republicans.

POLLSTER TRUMP’S MARGIN AMONG REPUBLICANS CLINTON’S MARGIN AMONG DEMOCRATS DIFFERENCE ABC News/Washington Post 83 87 4 CNN/ORC 87 89 2 Fox News 66 75 9 GWU Battleground 73 74 1 IBD/TIPP 76 77 1 Monmouth U. 70 82 12 Quinnipiac U. 75 85 10 RKM Research 79 84 5 Suffolk U. 71 78 7 Average 76 81 6 Clinton is doing better among her base than Trump is among his Data is rounded. Average of live-interview telephone polls conducted over the three weeks preceding Sept. 14.

Clinton leads among Democrats by an average of 81 percentage points, while Trump is ahead among Republicans by 76 points. That’s not a huge difference, but it’s meaningful. Trump has had problems with the GOP base since the primary season. Meanwhile, Clinton was cleaning up with self-identified Democratsduring the Democratic primaries, even as Bernie Sanders was doing well with independent voters. It’s also possible that Trump’s association with the Republican Party has caused some traditional Republican voters to call themselves independents, which makes the pool of independent voters more conservative leaning.

Indeed, many self-identified independents are not the moderate, persuadable swing voters they are often portrayed to be. As Amy Walter from the Cook Political Report has pointed out, independents usually lean towards one party or the other, even as they claim a nonpartisan label. Some lean Democratic or GOP. As Walter discussed, true independents only make up about 10 percent of all voters. Further, voters who typically favor the GOP make up a larger percentage of self-identified independents than they do of voters overall, which can make independents a Republican-leaning group relative to the electorate. In fact, the self-identified independents who consistently favor one party are often more ideologically extreme than those who identify with either party. That is, there is no reason to believe that independents should necessarily reflect the will of the overall electorate.

That’s especially the case when more voters identify as Democrats than Republicans. Independents are not at the center of a perfectly balanced seesaw. This is illustrated well by the most recent Pew Research Center report on party identification, released just a couple days ago. According to Pew’s yearlong study, 33 percent of registered voters identify as Democrats, 29 percent as Republicans and 34 percent as independents. In other words, the seesaw is often imbalanced.

The results from the most recent national polls and the Pew survey fit well with historical precedent. The way self-identified independents have voted in presidential elections since 1976 doesn’t always match the patterns of the overall electorate.

DEMOCRATIC MARGIN IN THE POPULAR VOTE YEAR OVERALL AMONG INDEPENDENTS DIFFERENCE 1976 +2 -4 -6 1980 -10 -25 -15 1984 -18 -28 -10 1988 -8 -14 -6 1992 +6 +6 0 1996 +9 +7 -2 2000 +1 -2 -3 2004 -2 +2 +4 2008 +7 +8 +1 2012 +4 -5 -9 Independents often don’t vote like the overall electorate Source: Roper Center

In fact, here’s an interesting historical tidbit: In the four elections decided by less than 5 points since 1976, the candidate who won independents lost the national popular vote every time. That includes Mitt Romney in 2012, who many Republicans argued would win because he was leading with independents. Less remembered is John Kerry’s loss in 2004; he had less support among self-identified Democrats than Bush did among self-identified Republicans and so lost the election despite edging out Bush among independents.

Kerry was also hurt by the fact that the Democratic edge in party identification was smaller in 2004 than in any other election in over 60 years. In fact, the network exit poll found as many voters identifying as Republicans as Democrats. If that were to happen again this year, as a recent Selzer poll out of Ohio indicates is possible, then this election could be closer than most polls have it. Usually, though, more voters identify as Democrats than as Republicans.

Of course, this doesn’t mean that Trump’s winning independents is a bad thing. They make up a sizable portion of the electorate, about 34 percent. It’s just that winning them isn’t a sure sign you’re winning the election. If Clinton is doing better among her base than Trump is with his and is able to hold down Trump’s margin with independents, she’ll probably win. If Trump, who has picked up ground in the polls over the past month, starts either blowing Clinton out among independents or starts doing better with his base, then he’ll have a real shot of winning the White House.