Trump campaign officials, however, latched on to those remarks as part of their long-term strategy. In their eyes, Biden’s comments offered an opening to differentiate the Democrat and their man on issues they believe will be crucial to their success with white working-class voters in 2020. “It allowed him to reclaim the high ground on the China issue,” one outside adviser to the campaign, who, like others, spoke on the condition of anonymity because they were not authorized to speak to the press, told me. “What Democrat now is going to be able to out-hawk Trump on China? Whereas if he’d signed a deal that was weak, those candidates would have ammunition.”

“The VP minimizes China at his own peril,” said David Urban, who led Trump’s Pennsylvania operation in 2016. “For him to come out and say that, it was a big, unforced error, and it does allow the president to show his leadership on the issue.”

The Trump campaign’s heightened focus on China and trade offers yet more evidence of the threat they feel Biden poses to the president’s reelection, and specifically to the blue-collar constituencies that Trump was able to swing in 2016. But perhaps more crucially, it indicates that Trump allies finally feel they’ve found their angle on those issues, after months of privately worrying that the president has few policy achievements to show for them beyond tough rhetoric. During the 2016 campaign, for example, Trump pledged to renegotiate the North American Free Trade Agreement (NAFTA), but his replacement plan, finalized with Mexico and Canada in November 2018, likely has a slim chance of passing the Democrat-controlled House. And while officials are optimistic that increasing tariffs on China is valuable for Trump from an optics standpoint, the fact remains that, under Trump’s watch, the country’s trade deficit with China has reached record highs—precisely what he argued the tariffs would guard against.

What’s more, the very voters Trump claimed would benefit most from his trade agenda may instead be shouldering the costs. Earlier this year, economists found that farmers and blue-collar workers in areas that supported Trump in 2016 were the main victims of the tariffs. “Workers in very Republican counties bore the brunt of the costs of the trade war, in part because retaliations disproportionately targeted agricultural sectors,” the authors of the study wrote.

“Trump is inflicting genuine economic costs on the country without necessarily achieving any particular goals,” Josh Meltzer, a senior fellow in the Global Economy and Development program at the Brookings Institution, told my colleague Derek Thompson last summer. “Instead, we’ve raised tariffs on our allies and alienated them, which has allowed China to portray us as the global outlier.”

Still, Trump and his allies believe that emphasizing fair trade over free trade—specifically through the lens of China—will be key to winning reelection in 2020. They say any studies showing that Trump voters are bearing the brunt of the White House’s trade policy, or any concerns about whipsawing in the market, come from those with an anti-Trump agenda. “The American people see what China is doing. The difference is the guys on Wall Street that had been mega-donors to Hillary Clinton want to see the global marketplace expand, so they don’t care about jobs in the U.S.,” Corey Lewandowski, Trump’s former campaign manager, told me. “That’s unfortunately where Joe Biden’s policies also fall.”