He was speaking at the legislative conference for North America’s Building Trades Unions (NABTU), a department of the AFL-CIO, and his remarks came just a week after the independent Amazon Labor Union won bargaining rights with the National Labor Relations Board for more than 8,000 workers at a Staten Island facility, which may be a key moment in a yearslong union battle at the tech giant.

Biden has been vocally pro-union since he took office, and his remarks may make relations tough with some of his old friends from the Obama administration.

In March, The Wall Street Journal reported that Jay Carney, Amazon’s senior vice president of global corporate affairs, had been sending Biden’s chief of staff, Ron Klain, messages about “perceived slights” against the company. Carney was press secretary for President Barack Obama and even director of communications for Biden when he was vice president. Amazon didn’t respond to Fortune’s request for comment.

Carney isn’t the only Obama-era official who left D.C. to join the tech sector. Campaign manager David Plouffe had a stint as SVP of policy for strategy for Uber, while Lisa Jackson, former administrator of the Environmental Protection Agency (EPA), now heads environmental policy and social initiatives at Apple.

It’s not uncommon for press secretaries to take corporate gigs or return to news positions once leaving their posts. Obama’s first press secretary, Robert Gibbs, began contributing to cable news channel MSNBC in 2013, later joined the board of directors for Yelp, and from 2015 to 2019 was chief communications officer for McDonald’s. The current White House press secretary, Jen Psaki, was reported by Axios on Friday to be in in talks with MSNBC to join the network when she leaves the administration in May.

“There is more bite under Biden”

In his remarks at the NABTU conference, Biden cited a White House Task Force on Worker Organization and Empowerment as evidence of his administration’s commitment to labor rights advocacy. The initiative, chaired by vice president Kamala Harris and labor secretary Marty Walsh, has the goal of improving awareness among workers of their rights to organize and collectively bargain.

Biden also referenced the Protecting the Right to Organize Act, colloquially known as the PRO Act, during his speech. Currently stalled in the senate, the PRO Act aims to reform the country’s creaky National Labor Relations Act, which first passed in 1935. 

Biden’s comments on Amazon are more than just empty rhetoric, says Joshua Freeman, a professor of history at CUNY’s school of labor and urban studies. The president’s administration already has a pro-union reputation, he says, meaning that when Biden tells Amazon to watch out, “it can carry weight.” 

More important, says Freeman, are Biden’s recent appointments at the NLRB and the Department of Labor, which include NLRB general counsel Jennifer Abruzzo and Secretary of Labor Marty Walsh. “These appointees already have made a significant difference, and I expect will continue to do so,” says Freeman. Abruzzo in particular has taken an aggressive approach to handling labor rights violations in her role.

Freeman says that Biden could do more to enact labor law reform since “realistically there is no chance of getting [the PRO Act] through the Senate.” The president, he says, could use procurement policy and tax enforcement to put pressure on anti-union companies.

“Compared to Trump, Obama, the Bushes, and Clinton,” says Freeman, “there is more bite under Biden, even if its effects so far are modest.”