Some of the Democratic Party’s most prominent lobbyists have been subtly — and in some cases not so subtly — reaching out to Members and Congressional staff urging against a lobby reform provision that would shine a new spotlight on K Street fundraising.

The provision at issue would compel lobbyists to disclose the campaign checks that they bundle together on behalf of candidate coffers. And lobbyists say that if it passes as part of a lobby reform bill, it will be to the detriment of the most junior and vulnerable Members.

Those are the Members, lobbyists argue, who most need the money-raising help from plum K Street Rolodexes — but who also would be the most vulnerable to charges from their opponents of being overly cozy with Washington, D.C.’s power brokers if such information became public. But advocates for reform groups say the lobbyists are less concerned for vulnerable Members and are truly worried about maintaining their own political clout. The Senate already has passed a package that includes the bundling provision, and the House is readying its own measure that could be unveiled as early as this week.

“Bundling is by far the most important provision in the lobby reform legislation,” said Fred Wertheimer, president of Democracy 21, which is part of a coalition of reform groups pushing for the bundling disclosure and other provisions.

He dismissed the lobbyists’ concerns about vulnerable Members and pointed to the support offered for the provision by Rep. Chris Van Hollen (Md.), who, as chairman of the Democratic Congressional Campaign Committee, is tasked with getting Democrats elected.

Meredith McGehee, policy director for another reform group, Campaign Legal Center, said most lobbyists simply are worried about not being able to make connections to new Members or to maintain their role as bundlers.

“I think this is more about lobbyists worrying about covering their political assets than worrying about vulnerable candidates,” McGehee said. “They don’t like having how they operate revealed publicly.”

But Democratic lobbyist Richard Gold, who heads the legislative practice at Holland & Knight, said the concerns he and his colleagues are voicing are real.

“The point we’re making with Members or staff is that you don’t want to end up doing something that has unintended consequences that end up hurting people just in order to avoid criticism from public interest groups,” he said. “The Members that it hurts the most are the Members that need to raise the most money, which is clearly the most vulnerable, those that are lowest in seniority.”

Gold said for senior, high-profile Members such as Energy and Commerce Chairman John Dingell (D-Mich.), raising money is a breeze. “If you’re [freshman Rep.] Bruce Blaley [D-Iowa] and you don’t know anybody here, you’re going to rely on lobbyists for help,” he said.

Another Democratic lobbyist — who like several others would speak only on background — said that in several meetings about other subjects with Members or Democratic staffers, lobbyists casually have brought up the bundling provisions. “They’re expressing it to Members and staff,” said this lobbyist. “Sometimes it’s very shorthand where they’ll say, ‘Don’t forget, the bundling provision sucks.’”

Already, advocates for the American Association for Justice, the trial lawyers group, have stepped up the pressure against the bundling measure, according to reform advocates.

A House Democratic leadership aide said arguments are coming from many sides and the party has yet to make final decisions on its lobbying package. “I don’t have a timeline yet,” this aide said. “There are pressures here and there, but we’re committed to making some real reform here.”

And, of course, not all Democratic lobbyists have inserted themselves into the debate.

“My colleagues and I at our firm sort of leave the discussions and deliberations on those issues to the Members themselves,” said Democratic lobbyist Jeffrey Peck of Johnson, Madigan, Peck, Boland & Stewart.

Still, another Democratic lobbyist questioned other K Streeters’ motives. This lobbyist said that some top fundraiser-lobbyists are worried about giving up some of their secrets of success. “It’s more about disclosing where lobbyists are raising their money from,” this lobbyist said. “Many lobbyists are guarded about where their fundraising sources come from, and they’re worried that if it becomes public other people can tap into it.”

But this lobbyist said the new class of Democrats could be more vulnerable if they take bundled contributions that are made public, because many of them got elected in scandal-plagued districts.

It’s a point not lost on Republicans.

One GOP lobbyist said that freshman Democrats such as Reps. Tim Mahoney (Fla.), who won in the district of ex-Rep. Mark Foley (R), and Zack Space (Ohio), who won the seat of now-jailed ex-Rep. Bob Ney (R), might be most vulnerable to criticism in their districts for receiving money raised with the help of checks bundled by lobbyists.

“They ran as reformers to the system that something was broken and it was a disgusting arrogant use of power, and what do these guys do the day they get to Congress? They’re having bundled checks given to them at Charlie Palmer where foie gras is on the menu,” said this Republican lobbyist of the possible campaign rhetoric that could come as a result of more public disclosures on fundraising.

But GOPers are worried about their own vulnerable candidates as well.

Gregg Hartley, a former top aide to House Minority Whip Roy Blunt (R-Mo.) who is now chief operating officer of Cassidy & Associates, said that lobbyists at his firm will comply with any new laws related to lobbyists and their donations.

But, he said, “I think it does cause a set of unintended consequences for Members and candidates themselves. There are going to be some lobbyist-fundraisers that say, ‘I don’t want to go through the hassle of reporting everything that gets raised as a result of an event I do, and then there being some negative inference from that.’”

He added: “Who is affected most by that? It’s the people who need the money the worst.”