Free trade deals have long been in the Republican Party’s wheelhouse. But ever since President Clinton was elected, Democratic administrations have pushed hard to open up new markets for American exports while allowing more competition from foreign firms at home. Opposition to free trade has come from Democratic members of Congress and organized supporters of the Dems, like labor unions and environmental groups.

So, it was somewhat surprising to see results of recent polls from the Pew Research Center and YouGov, which show that Democratic primary voters support free trade deals by a wide margin. According to YouGov, “Today, half (52%) of Democrats favor free trade, double the share who believe it is bad for the country (25%).” The Pew polls show that large majorities of Democratic primary voters would back candidates that support free trade.

If Democratic voters want free trade agreements, then, why have high-profile Congressional Democrats been so vocal in their opposition to the Trans-Pacific Partnership? Even stranger is the fact that Hillary Clinton has recently come out against the deal, after working as Secretary of State to craft and negotiate the arrangement. Other Democratic heavy hitters like Bernie Sanders oppose TPP.

Some argue, like Vox’s Matthew Yglesias, that this about money. He writes:

The emerging party position, in other words, is being driven by the specific concerns of labor unions and a few other advocacy groups rather than the broad views of party members, which seem more driven by loyalty to Obama and a vague cosmopolitanism.

This line of thinking puts too much faith in a few polls that don’t tell us very much about how people think. For one, if you look at the Pew poll, it shows that more Democratic party voters support free trade agreements rather than not. But the Pew poll also indicated that free trade agreements may not be a deal breaker among primary voters. Indeed, 34% of voters who took the Pew poll said they were completely indifferent on the issue.

The effects of free trade agreements on an individual person’s life are almost impossible to detect, and this has long been a thorn in the side of economists who have advocated for such policies. Theoretically, a free trade agreement will lead to significant job losses in specific sectors, as some business activities move to countries where it can take place more efficiently. The benefit of this is that domestic consumers have access to goods at cheaper prices.

But people are far more likely to fight against a policy that would cost them their job much more than one would fight for a 5% discount at Walmart. So free trade deals often enjoy support from the public altogether, but attract the ire of the groups of people who are most likely to lose if a deal goes through. Remember, politicians respond to money, but also to small but very passionate groups of citizens.

Another example of this dynamic is the debate over gun control. If you poll Americans, huge majorities are for gun control, but the issue obviously isn’t that important to them or they’d vote out the representatives who continually block gun control efforts.

This dynamic could explain why Democratic primary voters say they want free trade agreements. After all, they trust President Obama to negotiate in their best interests, and they like being able to get cheap foreign goods. But how far does this support go? It’s safe to say it animates them less than their belief that millionaires should pay higher taxes, or that gay people should have the right to marry. It’s not going to determine whom they vote for.

But for those whose jobs are at risk because of a free trade deal, they are fiercely opposed to any new trade deals at all. And a Democrat who comes out in favor of free trade risks losing not just labor money, but the invaluable support labor provides Democratic candidates in getting out the vote on election day.