“There’s an immense amount of relief,” Eckart said. “Make no mistake.”

Biden hasn’t secured the Democratic nomination yet, much less defeated President Donald Trump, of course. And even if Biden wins in November, there are no guarantees that he would prove any friendlier to K Street than Barack Obama, who once pledged that lobbyists “won’t find a job in my White House.”

Still, Democratic lobbyists expect a Biden administration would be easier to deal with than a Sanders one.

“You sort of know what a Biden administration looks like, and there’s a sense of comfort in that,” said Ivan Zapien, a lobbyist and former Democratic congressional staffer.

Biden, for instance, is less likely to attack companies routinely and by name on Twitter, as both Sanders and Trump have done — a point Monument Advocacy made in the memo it sent to clients after Sanders’ win in Nevada.

“Like President Trump, Bernie uses twitter to target businesses and industries,” the firm warned in its memo. “While his 9.1 million followers trail the President’s 40 million plus by a significant margin, his tweets are often just as biting and targeted at the C-suite, often by name.”

Matt McAlvanah, a former Obama administration official who wrote the memo, wrote in an email to POLITICO that Biden’s comeback “has calmed many nerves.”

“Businesses are hopeful that it’s a signal that we’re not entering an era of bouncing from one ideological extreme to the other,” he wrote.

But a Biden administration, if he were to secure the nomination and defeat Trump in November, could pose its own problems for K Street.

Biden has proposed legislation barring lobbyists from fundraising for politicians they lobby or donating to their campaigns. He’s also called for tougher lobbying disclosure rules and for prohibiting lobbyists from representing for foreign governments — a lucrative line of work on K Street.

“Joe has spent his entire career fighting to reduce the influence of money in politics, and has laid out an ambitious agenda as President for how he would clean up after the most self-serving and corrupt administration in history,” Michael Gwin, a Biden campaign spokesman, said in a statement to POLITICO.

Biden’s campaign, like many of his defeated rivals for the nomination, doesn’t accept contributions from lobbyists. But the former vice president’s decades in Washington mean he has plenty of former staffers and other allies on K Street, many of whom have tried to aid his campaign even if they’re not allowed to write him a check.

Larry Rasky, the treasurer of a super PAC backing Biden, runs the lobbying and public affairs firm Rasky Partners. He isn’t a lobbyist but was a registered foreign agent working for Azerbaijan’s government until August — something he wouldn’t be allowed to do under Biden’s proposal.

In a brief interview, Rasky said he wasn’t familiar with the details of Biden’s lobbying reform proposals but that he thought “lobbying works best when there’s as much disclosure as possible.”

“He’s going to do what he thinks is right, and I will live with the consequences of whatever he decides,” Rasky said.

Two Democratic consultants, Rodell Mollineau and Mark Paustenbach, have also advised the super PAC, Mollineau said in an interview. Neither are lobbyists, but their firm, ROKK Solutions, consults for corporate clients running Washington influence campaigns. Paustenbach worked on Biden’s 2008 presidential campaign.

Paul Bock, a Democratic lobbyist and former chief of staff to former Sen. Herb Kohl (D-Wis.), came to admire Biden while working for the Senate Judiciary Committee in the 1990s while Biden was its ranking member. While he’s not allowed to contribute to Biden’s campaign, he has urged others who aren’t lobbyists to do so.

“As you can guess, the campaign needs a couple things in January — money and volunteers — so I’ve attached an invitation to a January 8 DC event and below you’ll find a link for anyone who might want to go out to Iowa before the primary,” Bock wrote in an email in January to former chiefs of staff to Democratic senators.

The event Bock mentioned was a fundraiser at the offices of the law and lobbying firm Arnold & Porter Kaye Scholer. Former Sen. Chris Dodd (D-Conn.), who’s now a lobbyist at the firm, introduced Biden at the event.

Former Sen. John Breaux (D-La.), another old friend of Biden’s who’s now a lobbyist, showed up with Dodd at a fundraiser in Georgetown last year but didn’t write a check. “I’m sure I wasn’t the only non-paying customer,” he said with a laugh at the time.

Danny O’Brien, a former Biden chief of staff who’s now the top lobbyist for Fox Corporation, has helped connect supporters to the campaign as well.

Other former Biden staffers on K Street include Sudafi Henry, a lobbyist who represents clients such as Facebook, FedEx and PepsiCo; Tony Russo, the top lobbyist for T-Mobile; Jeffrey Peck, who lobbies for clients such as Deutsche Bank and Anheuser-Busch; and Chris Putala, a lobbyist whose clients include Comcast and T-Mobile, according to disclosure filings.

There are far fewer former Sanders staffers on K Street, although Michaeleen Crowell, his former chief of staff, is now a lobbyist at a Republican-leaning firm.

While none of the Biden alumni turned lobbyists are allowed to give to his campaign, others on K Street who aren’t registered lobbyists have done so.

Jennifer Park Stout, a former Biden aide while he was in the Senate, is now Snap’s vice president for global public policy but isn’t registered to lobby. She gave $2,800 to Biden’s campaign last fall.

Anthony Foxx, who was Obama’s transportation secretary and is now chief policy officer at Lyft, and Jay Carney, a former White House press secretary in the Obama administration who now oversees public policy at Amazon, were among the hosts of a November fundraiser for Biden in Washington, according to an invitation. Neither are registered lobbyists, allowing them to write checks.

Biden has even received a check from at least one Republican member of the influence industry: Juleanna Glover, a well-known Washington consultant who has advised a long list corporate clients but isn’t a registered lobbyist. She maxed out to Biden last fall.

“I will do anything that could be of assistance” to help Biden defeat Trump, she said.