Angered over last week’s vote on corporate-tax measure, Minority Whip Steny Hoyer (D-Md.) penned a stern letter Monday to his Caucus, chastising Democrats for voting against the party on a procedural vote — and blasting Republican business lobbyists for allegedly misrepresenting Democrats’ positions on the controversial bill.

In a rare letter from party leadership to rank-and-file Members, Hoyer told his fellow Democrats that it is unacceptable for Members to vote against the party when it hurts the Caucus’ ability to offer alternatives to Republican bills.

The Minority Whip cited the 11 Members who sided with the GOP on the bill’s rule vote last Thursday. The rule in question, Hoyer said, “barred consideration of any Democratic amendments or substitutes.”

Hoyer didn’t take issue with the final outcome of the bill, in which 48 Democrats — mostly Southerners and moderates — sided with the GOP. Rather, Hoyer said he and Minority Leader Nancy Pelosi (D-Calif.) are “greatly concerned” about the vote on the rule and about those Members who betrayed the Caucus, because it “threatens to undermine the unity” of the party.

“Undemocratic rules that are deliberately designed to silence our Caucus should always elicit strong, unified Democratic opposition,” Hoyer wrote. “The failure to oppose such rules will only foment future procedural transgressions by our opponents. And we must not stand for it. We must fight such undemocratic rules — as one.”

Rep. David Scott (D-Ga.), one of the 11 Members who voted for the rule, said, “it pains me deeply whenever I have to go in a different direction [than my party], but I am committed to doing what’s in the best interest of Georgia.” The measure contained a major tobacco buyout provision that would assist rural farmers in Georgia and other states.

Scott said that in this particular case he worked with Ways and Means Chairman Bill Thomas (D-Calif.) to craft the bill to best serve his constituents, and that he was committed to supporting it all the way through.

Rep. Ben Chandler (D-Ky.) said while in most cases he would agree with Hoyer on party unity, the corporate tax bill was a unique circumstance. He said his district’s economy is wedded to the tobacco industry and, “I need to have a 100 percent voting record for tobacco farmers in my state. For me there’s a bigger issue than all Democrats sticking together on one particular procedural motion,” he said.

That argument didn’t fly with other Democrats, however.

“Our message is unity,” said a senior Pelosi aide. “Our unity in itself appeals to voters and Democrats must demonstrate we are united. Speaking with one voice is part of our message.”

Rep. Charlie Stenholm (D-Texas), a conservative Democrat who voted against the rule but for the final version of the tax bill, said that for him, opposing the rule “was a softball,” given that the Democrats would have offered a more fiscally conservative alternative to the GOP version.

In another unusual move for a senior House member, Hoyer also took aim in his letter at four Republican business lobbyists who turned the screws on Democrats to vote for the Republican rule.

Hoyer cited a widely circulated e-mail from Fred Nichols, a lobbyist for the National Association of Manufacturers, who urged businesses and corporate trade associations to closely watch the outcome rule and “hold Members accountable for their votes.”

The e-mail was signed by three other GOP lobbyists: Dan Blankenburg of the National Federation of Independent Business, Chris Meyers of the U.S. Chamber of Commerce, and David Lugar, a lobbyist with Quinn Gillespie & Associates who said he was acting independently of his firm to help Republican leaders on the vote.

The lobbyists’ e-mail argued that Democrats must not use the lack of an alternative as an excuse for voting against the corporate-tax measure, because they didn’t properly seek a substitute bill.

“Please let your colleagues and clients know that any Democrat Member who is complaining about not getting a Democrat substitute needs to know that the Democrats did not submit one,” the e-mail said.

However, Hoyer said the e-mail “grossly mischaracterized” the Democrats’ effort to offer an alternative. He said Democratic leaders had been working for weeks on a substitute, but were told by Rules Chairman David Dreier (D-Calif.) — at the 11th hour prior to the vote — that a substitute “would not be made in order under the rule.”

Leadership aides suggested that the e-mail caused confusion and may have influenced the 11 Members to bolt the party on the rule. They said some Members worried that industry groups would use the rule to score lawmakers, which could hurt marginal Democrats in wooing business-minded voters.

“Over the last several days, I have taken steps to clarify this situation with various entities off of Capitol Hill, specifically informing them that Democrats do not appreciate or look lightly at external interference with Caucus positions on procedural votes” Hoyer told fellow Democrats.

Hoyer didn’t give specifics, but sources say the Whip and his senior staff have had several private conversations with K Street expressing their displeasure with the events leading up to the rule vote.

Those discussions have produced varying results.

A lobbyist for the Chamber of Commerce said that his group bucked the request and did not keep track of how Members voted on the rule.

But Lugar, a co-signer of the e-mail and the son of Sen. Dick Lugar (R-Ind.), criticized Hoyer for sending out the letter.

“It sounds to me like he is upset with his own party,” Lugar said. “The fact of the matter is that there is a group of Democrats who are more concerned about protecting their leadership position and not finding a way to help grow the economy.”

While Members and aides don’t expect any formal leadership retribution against either Members or business groups, they do believe that the e-mail strained relationships between Democrats and K Street.

But Stenholm sees some business groups coming around to the Democrats’ view. “Now that they’ve reflected on it, they realize is not in the business community’s interest to involve themselves in procedural votes,” he said, adding, “We’re not quite one big happy family, but we’re not splitting up.”

House Democrats have taken a more active role this cycle in courting the business community, and working behind the scenes to combat the Republican K Street project. Hoyer has taken a lead in the party’s charge in bringing businesses into the minority party fold.

“NAM’s e-mail misrepresenting the leadership’s position on a rule vote that shut down Democrats is one of the worst things the business community could have done to show its interest in working with House Democrats,” a senior Democratic House aide said. “Our goal is that this never happens again, and the only way to prevent this from happening again is to make sure from the beginning that this is not acceptable.”