House Ways and Means Chairman Charlie Rangel (D-N.Y.) and Senate Finance ranking member Chuck Grassley (R-Iowa) are at war over whose staff acted more unprofessionally in an incident involving negative news coverage of a Rangel tax proposal.

Rangel fired off letters last week to Democratic and Republican leaders on both sides of the Capitol, asserting that Dean Zerbe, a professional Republican staffer on the Finance Committee, may have violated Congressional rules.

Rangel alleges that Zerbe was a driving force behind news coverage including a Nov. 8 New York Times article that focused on the fact that some of Rangel’s campaign donors would benefit from a proposal he has introduced that is aimed directly at people who get a tax break for living and owning a business in the Virgin Islands. Grassley’s office flatly denies that.

Rangel met personally with Grassley, Zerbe’s boss, to discuss the matter and wrote a follow-up letter to Grassley last week. In his letter, Rangel said Grassley did not dispute that Zerbe approached at least two reporters and gave them information linking Rangel’s legislative actions to campaign contributions he received.

“In at least one instance, Senator Grassley acknowledges that Dean was responsible for a press article containing that allegation,” Rangel wrote to Democratic and Republican leaders.

According to Rangel’s letter, Zerbe initially denied any involvement in the stories until he was “confronted with evidence directly contradicting his assertions.”

A source said that evidence, which Rangel learned of, was a direct communication between Zerbe and a reporter.

But in a handwritten reply to Rangel on Dec. 16, Grassley said that Zerbe did absolutely nothing wrong and that Rangel’s own staff had acted unprofessionally in dealing with the matter.

“You appeared to emphasize the New York Times story that painted you in a very unfavorable light,” Grassley wrote. “As I said, my office had nothing to do with this story.”

Grassley also wrote that he encouraged Rangel to speak directly with the reporter about the matter.

Grassley wrote the only thing he acknowledged during the meeting was that someone forwarded a “public news story” to a reporter from Bloomberg News.

“I don’t believe this is beyond the Constitutional rights of anyone, including a Congressional employee,” Grassley wrote.

He then went on to allege that a Ways and Means staffer had sought to broker a deal where neither Rangel nor Grassley would be notified of the dispute if the Senate Finance staff met certain demands.

Grassley’s letter states that House Ways and Means staffer John Buckley said he would not take the issue to Rangel if the Finance staff did three things: “(1) write a letter to the New York Times saying that I did not believe there was any connection to your Virgin Islands legislation and campaign contributions (2) that I would stop my opposition to your Virgin Islands legislation and (3) that I would not publicly release a Treasury letter outlining very negative aspects of your Virgin Island legislation.”

“This is a very serious matter that you acknowledged was very ‘unprofessional’ behavior on Mr. Buckley’s part,” Grassley wrote. “Indeed, it arguably rises above ‘unprofessionalism.’”

Grassley said he hoped that the two men could overcome the episode and move on.

Rangel’s proposal would restore a three-year statute of limitations in the Virgin Islands for the Internal Revenue Service to cite errors in tax payments, except in the cases of fraud.

Rangel, meanwhile, has asked Congressional leaders to consider whether Zerbe violated House or Senate rules. Rangel argues that he could be in violation of the House rule that states Members, offices and employees “shall conduct [themselves] at all times in a manner which shall reflect creditably on the House of Representatives.” The Senate has similar rules covering Senators and employees.

Sources said that because Zerbe is a Senate staffer, that chamber would have jurisdiction in the matter. As a next step, Rangel could bring a complaint to the Senate Ethics Committee and ask them to look into Zerbe’s alleged actions.

“To me, the issue is whether Members of the House or Senate can be subjected to such a serious violation of protocol as to have an individual staff member suggest to the press that the Member’s conduct is motivated by political contributions, essentially accusing the Member of bribery,” Rangel wrote in his letter.

According to Rangel’s letter, during their meeting, Grassley suggested that Rangel was “making a mountain out of a molehill.” But Rangel said that even though he was not personally harmed by the incident, he worries about the precedent it sets.

“No staff person is entitled to one personal attack on a Member of Congress and that message must be clear,” Rangel wrote.

Rangel argued to Grassley that if a Member of Congress were to imply that another Member’s actions were driven by campaign contributions it would be a very serious matter — one that could result in an ethics investigation or subject to a matter of personal privilege on the floor.

“My question to you is: What recourse does a Member of Congress have when an individual staff member encourages the press to write stories questioning his or her integrity?” Rangel wrote to Grassley.

That letter, as well as the one Rangel addressed to leaders, was sent to Speaker Nancy Pelosi (D-Calif.), House Majority Leader Steny Hoyer (D-Md.), House Minority Leader John Boehner (R-Ohio), Senate Majority Leader Harry Reid (D-Nev.), Senate Majority Whip Dick Durbin (D-Ill.) and Senate Minority Leader Mitch McConnell (R-Ky.).

Copies of both letters were obtained by Roll Call.

“The letters speak for themselves,” said Matthew Beck, a spokesman for the Ways and Means Committee.

“This is not a personal issue with me,” Rangel wrote. “My reputation and political position can easily withstand malicious actions by an individual staffer. However, I do have serious concerns for the precedent that would be set and the potential for harm to other Members and the institution as a whole. This is a serious matter.”

Meanwhile, an ethics expert said that the principle Rangel is using is designed as a catchall to cover wrongdoing not specifically spelled out in House and Senate rules. While the catchall is valuable in many instances, he said, many ethics lawyers and experts are concerned about the ease with which it is being used.

“That is a principle that has been used very frequently, and I think some would say too frequently,” the expert said. “It basically says: ‘You didn’t do anything wrong under the rules, but I didn’t like what you did.’”

The expert also said Rangel’s complaint raises concerns about First Amendment rights and the free flow of information — a practice that happens all the time on the Hill.

“The idea that only things you like going to the media are credible and things you don’t like going to the media are not credible doesn’t hold a whole lot of weight,” the expert said.