Joe Biden would be well to the right of President Trump on trade if he enters the 2020 race.

The former vice president's record could help him to pick off pro-business Republicans. But it could be a problem for him in the Democratic primary, given that the party has long been torn between proponents of trade deals, such as Presidents Bill Clinton and Barack Obama, and unions and liberal activists who see such deals as threats to the working class and the environment.

Biden backed most of the major trade deals and related issues that came up during his 36 years as a Delaware senator, including the North American Free Trade Agreement, establishing Trade Promotion Authority for the White House, and approving Permanent Normal Trade Relations with China. In President Obama’s administration, he was again a supporter of the Trans-Pacific Partnership, the proposed trade deal among Pacific Rim nations, and again of Trade Promotion Authority for the president to carry out the deal.

That record makes him an anomaly in a field crowded with Democrats such as Sens. Elizabeth Warren, D-Mass., Bernie Sanders, I-Vt., and Kamala Harris, D-Calif., whose main criticism of Trump’s trade policies is that he hasn’t lived up to his tougher rhetoric or done enough to ensure that the U.S.’s trade partners live up to their end of the bargains.

[Related: Trump says that he and Bernie Sanders agree on trade]

“In the Democratic party he was in during his three and a half decades in Congress, he was right of the center of gravity, but not abashedly so,” said Dan Griswold, senior research fellow at George Mason University’s Mercatus Center. Griswold placed him in the tradition of Obama and Clinton.

But the party has changed since the presidencies of Clinton and Obama, said Robert Borosage, a veteran liberal activist and co-founder of the Campaign for America’s Future. He pointed to the case of the Trans-Pacific Partnership, which Obama negotiated and Biden lobbied Congress on.

“The people on the progressive side of the argument have basically won the debate on trade inside the party. TPP was dead long before Donald Trump was elected. It was dead with the Democrats in Congress,” he said.

Lori Wallach, director of Public Citizen’s Global Trade Watch program, agrees the issue will be a problem for Biden now that liberal activists are resurgent.

“Biden’s record stands for itself,” she said. "He has been on the opposite side of most congressional Democrats and important Democratic constituencies on most trade issues for decades."

Bryan Riley, trade policy analyst with the right-of-center National Taxpayers Union, countered that the issue isn’t toxic among all Democratic voters, even if the more hardcore activists who dominate primaries oppose it. An October poll by the Brookings Institution found that 64 percent of Democratic primary voters believe trade creates more jobs than it costs.

[Also read: Tariffs from Trump's trade wars are hurting the economy, budget office finds — but only barely]

“Many candidates may be pandering to powerful union and environmental groups … Biden’s record suggests his policies would be more pragmatic,” Riley said.

Biden has never characterized himself a pure free trader. He has even previously endorsed some of the hard-line policies that Trump has. In a 2007 presidential debate hosted by the AFL-CIO, he proposed renegotiating NAFTA by dragging the U.S. trade partners to the table.

“A president’s job is to create jobs, not to export jobs, and the idea that we are not willing to take the prime minister of Canada and the president of Mexico to the mat to make this agreement work is just a lack of presidential leadership. I would lead, I would do that,” Biden said.

In a follow-up debate that year hosted by the Des Moines Register, however, Biden opposed the idea of hitting China with tariffs even when the issue was framed as protecting U.S. consumers from unsafe products. “No, I'm not willing to go there. You don't need to start a tariff war,” he said.

Biden did oppose some deals and back some protectionist measures, such as steel import quota in 1999, noted Griswold, the Mercatus Center scholar. But on the big, important votes, he backed free trade pretty consistently, Griswold said, particularly NAFTA.

In a 2017 speech to the World Economic Forum in the last days of the Obama administration, Biden warned against "revert(ing) to political small-mindedness — to the same nationalist, protectionist, and isolationist agendas that led the world to consume itself in war during in the last century."

His backing of permanent normal trade relations for China is noteworthy too, Griswold added, for the contrast it shows with Trump’s policies. Just last month, The U.S. trade representative under Trump, Robert Lighthizer, went out of his way to praise House Speaker Nancy Pelosi, D-Calif., for having opposed permanent normal trade relations, lauding her “foresighted leadership” in doing so.

Biden has been careful throughout his career to say he supports trade only so long as it benefits most people, characterizing himself as backing “fair trade,” not free trade, and sympathetic to those hurt by the resulting economic shifts.

In a speech last November at Owingsville, Ky., Biden argued that Trump’s stance on trade, and economics in general, was “deliberately designed to appeal to the legitimate frustrations of a lot of working-class people by finding a scapegoat, the ‘other’ ... It’s an old, old method." After Trump’s election in 2016, Biden warned against characterizing the voters he won in Rust Belt states as bigoted. “Barack Obama won these people," he said. "They are not racist.”

Borosage argues that while Obama himself was popular with those voters, it wasn't because of his trade policies, and those policies are even less popular now. “Trade is a big deal with the industrial workers, the white working-class voters, and Trump makes it an even bigger deal by trying to steal the progressive position and abandon the Republican position,” he said.