Vice President Joe Biden recently noted that Democrats “haven’t spoken enough” to working-class voters. He warned that failing to communicate with these voters was alienating a core portion of the Democratic Party’s traditional base.

Biden’s comments highlight one of this election’s core themes: persistent debate over the direction of working-class voter support. Nate Silver, for example, argued that Trump’s working-class support is largely a myth. However, a recent Gallup study showed a more complex picture. Working-class loyalties are, at best, divided.

In spite of the attention this issue receives, relatively little discussion takes campaign contributions into account. Yet when we look at where money is going so far this year — and at how much is being donated — we see that Biden might be right to caution his party. Donations to Democrats are down, while Republicans are enjoying a small but significant increase. These patterns may suggest an emerging shift in labor donor priorities.

Organized labor provides the most revealing example. Money from labor to Democrats is down significantly since 2012 (and since 2008). According to Center for Responsive Politics (OpenSecrets.org) data, total labor donations to Democrats have declined roughly 35 percent as compared with 2012 levels. There is still time before the election. However, a windfall in giving before November would be required to make up the $21 million gap between current levels and 2012.

This decline is not driven solely by one industry. The data follows the same pattern when looking at subcategories of labor donors. Industrial, public sector, and trade unions are all giving at least 30 percent less money to Democrats in 2016. (Teachers unions stand out as the main exception.)

Moreover, expenditures that CPR refers to as “outside spending” have also declined across most labor categories. In the aggregate, total labor expenditures independent from a campaign committee are down $10 million (14 percent) for Democrats.

One possible explanation for declining donations is falling union membership. Shrinking unions might simply have less money to give. But this wouldn’t explain why contributions directed to Republicans are steady — and in some cases up slightly — from 2012.

Overall, Republican candidates have already matched the total contributions they received from labor in 2012. And since Democrats are now receiving less money, the Republican Party’s share of total labor contributions has nearly doubled, from 9 percent to 15.

Money from specific unions follows these patterns. The AFL-CIO publicly endorsed Hillary Clinton, yet almost half of its donations to candidates and parties have gone to Republicans. In 2012, Republicans received only 18 percent of the AFL-CIO’s total contributions. The same pattern holds for other top 10 donors. The share of money Republicans receive from the Carpenters & Joiners, Laborers, and Plumbers/Pipefitters unions have all doubled.

It’s true that the total volume of money to Republicans remains relatively small. The $7 million Republicans received thus far is dwarfed by the $40 million enjoyed by Democrats. But comparing these totals misses the point. Since less money is being spent overall, it’s telling that Republican donations remain steady. Organized labor isn’t just donating less money across the board. These groups are fundamentally reallocating their funds, increasing the share of money they give to Republicans.

Possible explanations for these patterns include a growing sense of economic disenfranchisement among working-class voters. Data also suggests race plays an important role. Public opinion data offered by PRRI/Brookings and Gallup reports provide some evidence for both of these arguments.

These explanations tend to focus too narrowly on Trump and whether he has unique appeal for (white) working-class voters. But Trump receives essentially no money from labor. If anything, the contributions data suggests a more fundamental shift in working-class attitudes.

Of course, it’s important to recognize the growing role of outside money in recent campaigns. There is less given directly to parties and candidates in general. But conservative PACs currently hold eight of the top 10 positions in total spending. In 2012, the split was six conservative and four liberal.

To be sure, any movement of labor from Democrat to Republican is still an evolving process, and it is far from universal. Most major organized labor voices — including the heads of unions like the AFL-CIO — still publicly support the Democratic Party and endorse Clinton. But campaign contributions lend validity to Biden’s cautionary comments. Democrats are receiving significantly lower volumes — and lower shares — of the limited supply of organized labor donations.

Jeffrey Kucik is an assistant professor of political science in the Colin Powell School at City College of New York.

Ashley Moraguez is an assistant professor of political science at the University of North Carolina Asheville.

For all their disagreements, Hillary Clinton and Donald Trump overlap on one key issue: their opposition to free trade. The candidates have both come out against the Trans-Pacific Partnership, and they have expressed concerns about the US’s existing trade deals.

Unifying the candidates is a shared belief that trade endangers US jobs. Clinton promises to “level the global playing field for American workers,” while Trump stated that employees are “being crushed” by trade.

Is this focus on working-class America really anything new? While Clinton aligns with Democrats’ recent position, we argue that Trump’s populist appeals signal a fundamental break from Republicans.

Prior research shows that party positions on trade shifted during the 1990s. In spite of Bill Clinton’s support for the North American Free Trade Agreement, Democrats were less willing to support liberalization than they had been in the past. At the same, Republicans adopted free trade as a core component of their platform.

A new study in The Forum examines the determinants of congressional votes on the 11 trade agreements ratified since 2001. Our evidence shows that the main difference between Democrats and Republicans in the House of Representatives is their sensitivity to labor issues. Democrats are heavily influenced by district unemployment and campaign contributions from organized labor, whereas Republicans are unswayed by these factors.

Analyzing roll call data on the 11 most recent trade agreements, Democratic House members from districts with high unemployment supported ratification at much lower rates than did other members. In addition, Democrats received significantly larger contributions from organized labor. And this money matters. Those who receive contributions of more than $100,000 are 35 percent less likely to vote in favor of trade agreement ratification than the average House member.

Clinton’s emphasis on jobs is, therefore, consistent with her party’s recent position. After all, Democrats only voted in favor of ratification 36 percent of the time since 2001, and only when labor was not a pressing concern.

Trump’s opposition to trade is more curious. Republicans supported those same 11 trade agreements with near unanimity. On the Republican side of the aisle, there is no evidence that members are swayed by district unemployment rates. They also face less direct pressure for protection, receiving an average of $20,000 in campaign contributions from labor interests, compared with $120,000 received by Democrats, on average.

Given these trends, Trump’s campaign promises depart significantly from the Republican Party recent support for trade. In fact, Trump’s populist, pro-labor economic platform is bolder than Clinton’s. Trump wants to raise tariffs by as much as 45 percent and to retreat from the US’s trade agreements altogether.

While Trump makes big promises, it would be a mistake to think his positions are ad hoc. His appeals reveal fundamental changes occurring in the Republican base—one in which the voices of working-class interests are becoming louder. Trump is making a concerted effort to reach voters with a growing sense of economic disenfranchisement. The result is a Republican frontrunner standing in direct opposition to his party’s traditional support for liberalization.

This shift among Republicans is likely to have bigger implications moving forward, especially for pending trade agreements like TPP. Clinton’s opposition should be taken in stride; all recent Democratic candidates expressed skepticism toward free trade on the campaign trail.

In 2008, Obama stated his desire to renegotiate NAFTA and to abandon the three agreements he would inherit from Bush. Eight years later, NAFTA remains untouched, and agreements with Colombia, Panama, and South Korea have entered into force. The most likely outcome of a Hillary Clinton presidency is a continuation of pro-trade policies that started under Bill Clinton and NAFTA.

The implications of Trump’s statements are less clear. He stated that he “does not fear a trade war” and has already alienated key US trade partners, most notably China. But his declarations are perhaps less interesting than what he represents—a new, powerful anti-trade segment of the Republican Party. For example, Orrin Hatch (R-UT) said that TPP fell “woefully short” of expectations, and Mitch McConnell (R-KY) implied the vote would suffer lengthy delays.

Splintering among Republicans means that TPP’s survival will require support from both parties. This is where history might be on TPP’s side. In spite of the broad gap between Democrats and Republicans, eight of the past 11 free trade agreements passed through the House with — or because of — support from both sides of the aisle.

CAFTA-DR is perhaps the most telling example. Republicans voted against CAFTA-DR in unusually large numbers (27 members), yet it passed through the House with support from 15 Democrats, who tipped the narrow margin in favor of ratification.

Obama’s ability to secure a similar cross-party coalition will determine TPP’s fate. TPP’s passage is going to require convincing a Republican Party that is increasingly concerned with labor interests and the costs of free trade.

Jeffrey Kucik is an assistant professor of political science in the Colin Powell School at the City College of New York. His research examines the domestic politics of international trade, focusing on the formation and design of international trade law.

Ashley Moraguez is an assistant professor of political science at the University of North Carolina Asheville. She researches American political institutions, particularly bargaining between the legislative and executive branches.