Biden is set to attend a fundraiser Thursday night at the Philadelphia home of Comcast executive David Cohen, according to an invite first published by Politico and later obtained by HuffPost. While Cohen is not a registered lobbyist, he does oversee the cable giant’s massive Washington lobbying operation, which spent more than $4 million and involved more than three dozen lobbying firms in the first quarter of 2019 alone.

Former Vice President Joe Biden ’s 2020 campaign won’t accept donations from federal lobbyists ― but a fundraiser scheduled for the first day of his campaign also shows the limitations of such a pledge.

ASSOCIATED PRESS Former Vice President Joe Biden is expected to launch his 2020 presidential campaign on Thursday morning.

“Biden for President will not accept contributions from registered federal lobbyists, corporate PACs, or registered foreign agents,” Biden spokesman Bill Russo wrote in an email. “Additionally, as Vice President Biden has previously said, he will not be a part of a Super PAC.”

The fundraiser will take place just hours after Biden, one of the frontrunners for the Democratic nomination to challenge President Donald Trump, launched his campaign on Thursday morning. The fine print at the bottom of the invite indicates the campaign won’t take direct donations from lobbyists, corporate PACs or unions.

An invite to a fundraiser for former Vice President Joe Biden's presidential campaign in Philadelphia on April 25.

Biden’s decision not to take federal lobbyist cash leaves South Bend, Indiana, Mayor Pete Buttigieg as the only candidate in the top tier of the Democratic field taking donations from K Street. New Jersey Sen. Cory Booker, California Sen. Kamala Harris and former Texas Rep. Beto O’Rourke have all returned donations from lobbyists. (Lesser-known candidates, including former Rep. John Delaney and Colorado Gov. John Hickenlooper, are also taking donations from lobbyists.)

Progressives have pushed Democratic candidates not to take donations from lobbyists or corporate PACs, arguing that passing up donations from those groups will help clean up the party’s image and free its candidates to craft policies to combat economic inequality and entrenched Washington interests.

But Biden’s Day One fundraiser highlights how corporations can still find ways to influence politicians, even with those safeguards in place. Cohen, a former top aide to then-Philadelphia Mayor Ed Rendell, is a major political player in Pennsylvania and Washington, and Comcast’s lobbying operation is considered among the nation’s most powerful. But it’s fairly easy for Cohen and others to avoid registering as lobbyists, as long as they don’t spend more than 20 percent of their time directly interacting with lawmakers and staff.

Biden isn’t the only candidate taking advantage of such loopholes. For instance, Daniel Cruise, the head of government affairs for Juul, donated $2,800 to the presidential bids of both Harris and New York Sen. Kirsten Gillibrand. Cruise is not a registered lobbyist. It’s also not the first time Cohen has taken advantage of such a loophole ― he was able to donate to President Barack Obama and Biden’s 2012 reelection bid, which also eschewed lobbyist donations.

Biden’s fundraiser is part of a large-scale effort to match the impressive first-day fundraising totals of Bernie Sanders and O’Rourke, who both brought in more than $6 million, mostly from small donations over the internet. Biden, who lacks a comparable track record of raising money online, is instead counting on donors cutting checks near the federal maximum of $2,800.

Beyond Cohen, the list is a who’s who of influential Philadelphia-area Democrats. Former Rep. Bob Brady, a longtime party boss in Philadelphia, is a co-host, alongside Rendell, former Philadelphia Mayor Michael Nutter and Independence Blue Cross CEO Dan Hilferty. Eight members of Congress, including Pennsylvania Sen. Bob Casey and Delaware Rep. Lisa Blunt Rochester, are also set to attend.

“The response has been overwhelming,” said Alan Kessler, a Philadelphia lawyer who is co-hosting the fundraiser. He said he was expecting about 125 to 150 people at the event, and even more checks from people who couldn’t make it.

“I haven’t had a ‘no’ yet,” he said.

This story has been updated with comments from a Biden spokesman and Kessler as well as more information on other candidates’ fundraising.

Amanda Terkel contributed reporting.