Politicians like to say they hate lobbyists. This is false. They love lobbyists and they love being lobbied. What politicians hate is being lobbied in public, in earshot of their constituents.

Keeping disagreements and policy debates behind the closed doors of Capitol Hill and K Street animates Democrats' fight for campaign finance restrictions. But it also lies at the heart of the Republican leadership's war with Tea Party groups.

Take Byron Dorgan, the former Democratic senator. In his 2006 book he complained of “legions of lobbyists” bringing “barrels of political donations.” Dorgan's wife, Kimberly, has since 1999 been a lobbyist for the life insurance industry. At least five of Dorgan's former chiefs of staff are lobbyists. Lobbyists were his second largest source of campaign contributions, according to data from the Center for Responsive Politics. And today, Dorgan is the co-chair of the “government relations practice” at lobbying firm Arent Fox.

Senators and congressman like lobbyists for many reasons. They like being flattered and feted by lobbyists. Lobbyists work as volunteer fundraisers, and they overwhelmingly support incumbents. Also, lobbyists hire congressional staffers (who then raise money for their former Hill bosses), and eventually the lobbyists hire lawmakers to be lobbyists.

Most importantly, if lobbyists argue with lawmakers, they do so discreetly. That’s what annoys lawmakers so much about “outside groups” – they make the fight public. Nothing upsets an incumbent more than activists going “behind his back” and speaking directly to his constituents. Ideological groups and business interests — they should have to run the K Street gauntlet, lawmakers think.

New York Sen. Chuck Schumer is the Senate Democrats' top fundraiser, and not coincidentally, he also leads the Democrats' charge in cracking down on outside group spending.

Schumer knows how to play the K Street game. Right after Democrats took over the Senate in January 2007, Schumer called together top hedge fund executives and, the New York Times reported, told them, "If you want Washington to work with you, you had better work better with one another." Translation: Start lobbying for real. Hedge funds responded, and Schumer and Senate Democrats were the prime beneficiaries. Within a few months, Schumer’s banking staffer left for K Street, picked up a bunch of hedge fund clients and started raising cash for Schumer.

You can see why Schumer and friends prefer it when businesses run the K Street gauntlet, as opposed to the messier alternative: businesses communicating with constituents in order to whip the lawmaker.

But the GOP leadership has its own problems with “outside groups.” Sens. Ted Cruz, Rand Paul and Mike Lee at times utilize the unseemly Tea Party whip operation: These first-termers stake out a position and work with Beltway organizations like Heritage Action or the National Rifle Association, who then blast their members in the home state or district of wavering Republicans. The result is uncomfortable for the wavering Republicans -- hundreds of phone calls, thousands of emails, dozens of angry neighbors at local town hall meetings.

After the government shutdown, Sen. John McCain -- a champion of campaign finance restrictions and scold of outside groups -- told a local radio station, “I can tell you what is resented amongst Republicans, and that is that Sen. Cruz and Sen. Lee are raising money for an organization that is running ads attacking Republican senators.”

Conservative Senate staffers tell me that in closed-door GOP meetings, senators have unloaded on Cruz and Lee for associating with groups that run ads in their home states.

Cruz, in his filibuster that preceded the shutdown, said, “We hear more complaints about ‘I don't like all the phone calls I am getting from my constituents' than we do about Obamacare. It is apparently an imposition on some members of this body for their constituents to pick up the phone and express their views. It is viewed as somehow illegitimate.”

Party insiders say the problem isn’t constituent communication, but that the communication is “misleading.” Do the outside groups mislead constituents? This is a judgment call. I was not alone in thinking a government shutdown would never defund Obamacare, but Cruz and his allies in the outside groups promised they could.

Groups like the Senate Conservatives Fund certainly attack their GOP targets as harshly and uncharitably as the parties generally attack one another. Is this out of bounds?

Incumbents can deal with closed-door arguments. Campaign-style attacks can become demagoguery. But is constraining businesses and ideological groups within the K Street gauntlet really a better way to debate?

Timothy P. Carney, the Washington Examiner's senior political columnist, can be contacted at tcarney@washingtonexaminer.com. His column appears Sunday and Wednesday on washingtonexaminer.com.