Thursday saw some bipartisan dealmaking from the unlikeliest of allies in the unlikeliest of places: Progressive Rep. Alexandria Ocasio-Cortez (D-NY) and conservative Sen. Ted Cruz (R-TX) happily agreed — over Twitter — to work on a bill together.

So what’s the subject one of the most left-wing members of Congress and one of the most conservative senators can agree on? A lifetime lobbying ban for members of Congress after they retire or lose their seats.

“If we can agree on a bill with no partisan snuck-in clauses, no poison pills, etc — just a straight, clean ban on members of Congress becoming paid lobbyists — then I’ll co-lead the bill with you,” Ocasio-Cortez tweeted at Cruz.

“You’re on,” he replied.

Here’s something I don’t say often: on this point, I AGREE with @AOC Indeed, I have long called for a LIFETIME BAN on former Members of Congress becoming lobbyists. The Swamp would hate it, but perhaps a chance for some bipartisan cooperation? https://t.co/jPW0xkH2Yy — Ted Cruz (@tedcruz) May 30, 2019

A few hours later, conservative Rep. Chip Roy (R-TX), Cruz’s former chief of staff, had offered to co-sponsor a lifetime lobbying ban bill in the House, and progressive Sen. Brian Schatz (D-HI) had agreed (in all caps) to sign on in the Senate. Of course, that bipartisan momentum could hit a block if Senate Majority Leader Mitch McConnell opposes the bill.

It wasn’t that some of the most conservative and liberal members just woke up and decided to make a deal on a recess week for Congress. The decision came on the heels of a new report from the nonprofit consumer advocacy organization Public Citizen about the number of lawmakers who left Congress in 2018 and went on to work as lobbyists and consultants.

Out of 44 members of Congress who either retired or lost their seats in the midterms, 26 went on to get jobs at lobbying firms — nearly two-thirds, the Public Citizen report found. The vast majority of them were Republicans, but one notable Democrat who went from the Hill to a lobbying firm was former House Democratic Caucus Chair Joe Crowley, whom Ocasio-Cortez defeated in 2018.

Members of Congress in both parties are talking a big game about cleaning up Washington corruption, and House Democrats passed a major anti-corruption bill earlier this year that would crack down on lobbying. But even with the rare bipartisan momentum, some money in politics experts fear a blanket ban could have unintended consequences — pushing more people into so-called “shadow lobbying.”

The “revolving door,” briefly explained

Just because senators and members of Congress retire or lose their seats doesn’t mean they leave Capitol Hill.

Departing lawmakers are highly sought after by lobbying firms, especially if they held a position of power during their Hill tenure. They’re so desirable because they know exactly how things work and whom to talk to in Congress.

“What we’re talking about here is hiring someone not just for their expertise but also their network and knowledge of how the process works and what levers to pull — their knowledge of what has occurred and what debates have happened,” said Dan Auble, senior researcher at OpenSecrets (which published its own report on members of Congress who recently joined law and lobbying firms on Thursday).

That insider knowledge is exactly what makes these members more effective than other lobbyists. A 2009 study, “Lobbying and Policy Change,” conducted by five political scientists, found that a consistent predictor of a lobbying firm’s success was if it hired more lobbyists who had been government officials in the past. In fact, groups with so-called “revolving door lobbyists” prevailed at their lobbying efforts 63 percent of the time.

Not each lawmaker holds the same appeal. Senators are always sought after, no matter how much time they’ve spent in the upper chamber.

“The Senate is such an exclusive club to begin with, they’re highly valued,” Auble said.

Members of the House have to meet a higher threshold to garner the interest of firms, which typically are only looking for House members who held important committee or subcommittee chairmanships, or who held a position of power within their party.

The Public Citizen report details 26 lawmakers who joined lobbying firms this year, and even more who joined corporate boards, law firms, and broadcast networks. Of those, just two have actually registered as lobbyists. Others are serving as consultants — what Alan Zibel, the research director who compiled the Public Citizen report, sees as a convenient workaround to actually having to register.

“The fact you can advise your colleagues on how to lobby and who to lobby, how to write your papers and which language to use ... it’s lobbying in everything but the actual name,” Zibel said.

Some notable names in the Public Citizen report include:

Former Sen. Joe Donnelly (D-IN), who lost his Senate reelection bid in 2018. Donnelly went to work for the major lobbying firm Akin Gump, where he’s advising financial services, defense, and health care policy clients.

Former Secretary of the Interior Ryan Zinke (also a former Republican Congress member from Montana). After leaving the Trump administration in December amid ethics investigations, Zinke is now consulting for a Nevada-based gold mining firm called US Gold Corp.

Former Rep. Lynn Jenkins (R-KS). Jenkins started her own lobbying firm, LJ Strategies LLC, while she was still in office.

Former Rep. Joe Crowley (D-NY), the onetime chair of the House Democratic Caucus. Crowley joined DC’s largest law and lobbying firm Squire Patton Boggs in February, working on an industry-funded bipartisan policy center, where he’s focusing on infrastructure issues. Crowley is also on the board of the investment firm Northern Swan Holdings Inc., which recently made a $96 million investment in legal marijuana cultivation efforts in Latin America. Former Sen. Tom Daschle is also working on the cannabis efforts.

The possible unintended consequence of a lifetime lobbying ban: more “shadow” lobbying

Ocasio-Cortez and Cruz are far from the first lawmakers to think their colleagues should truly leave Capitol Hill once they’re out of office. There are already numerous bills out to put some kind of a ban on members of Congress becoming lobbyists after they leave the Hill, with time limits ranging from multiple years to a lifetime. Whether any of them will actually solve the problem Ocasio-Cortez and Cruz are interested in, however, is another question.

Auble and Zibel said there’s already a big problem with loopholes that a blanket ban on lobbying might not fix — because a number of former members of Congress don’t actually register as lobbyists. There are plenty of other workarounds, such as taking on the title of “strategic adviser” or “consultant.”

Current rules mean that as long as former members of Congress and others don’t directly contact government officials themselves, they don’t have to register as lobbyists. But they can still tell other people in their lobbying firm whom to call and what to say.

“They still have a lot of opportunity to point their clients and the firms they work for toward which levers in Congress to pull without actually having to make the calls themselves, which absolves them of the requirement to file,” Auble said.

And as the current rules stand, members of Congress must wait a certain amount of time to start lobbying on Capitol Hill. Former House members need to wait a year, and former senators need to wait two years. But the current rules say nothing about wait times to lobby the White House and executive branch.

For instance, former Rep. Ileana Ros-Lehtinen, a Republican from Florida, registered as a lobbyist on behalf of MDIF Media Partners, a media investment fund, which she represents on US relations with Poland.

“The fact she can lobby the State Department is ridiculous,” Zibel said. “I think a five-year ban would really deflate the power of these connections.”

While there’s now new momentum from Ocasio-Cortez around a lifetime lobbying ban, not everyone is so sure that would actually deter the lobbying culture of Washington DC.

Auble, for one, worries it could actually give rise to more “shadow lobbying,” where former members of Congress still go to work for firms but even fewer actually register as lobbyists. He noted that of the Congress members who departed in 2018 to join lobbying and consulting firms, just two (including Ros-Lehtinen) actually registered.

In addition to bipartisan efforts to impose a lifetime ban on members of Congress lobbying, there are plenty of bills to beef up transparency, including provisions in HR 1, the sweeping anti-corruption bill House Democrats passed as their first major priority of the year.

There’s undoubtedly momentum on the issue. But until McConnell greenlights a vote in the Senate, a lobbying ban is going nowhere.