COLUMBIA--The House Republican Caucus has returned a $3,500 contribution from the S.C. Chamber of Commerce, one of the state's most powerful lobbying groups.

Lawmakers worried the check could be perceived as a payoff for a banner legislative year for business interests. But the caucus' action also is the most public indication of an underlying divide developing between the two political powerhouses.

In a letter mailed Wednesday, Majority Leader Jim Merrill sent back an unopened envelope containing the $3,500 check from the chamber, which represents businesses statewide.

The chamber's donation, the maximum allowed under law, pays for a membership on the caucus' Business Round Table, an inner circle of allies that get prime access to legislative leaders.

"The reason for (returning the donation) is because your letter, while certainly not intended as such, could be construed as a quid pro quo proposal," Merrill wrote to chamber President Hunter Howard.

A rift began to materialize in February after the chamber, for the first time in recent memory, didn't send a $3,500 contribution during an annual caucus fund-raising campaign. Instead, Howard wrote a letter to Merrill that said the chamber would delay its donation until it graded lawmakers' handling of business issues during the 2005 legislative session.

The chamber "is closely following the information contained in (our) Legislative Scorecard to make important financial decisions regarding political candidates, officeholders and organizations who seek political contributions," Howard wrote.

Merrill, who leads the caucus as the majority leader, said he perceived the letter as a threat. "I don't think it's intended as a threat but I think it can be perceived as an overly aggressive statement," Merrill said in an interview.

Last week, the chamber met with Merrill and presented the check. The Daniel Island Republican said the caucus solicits donations before sessions start to avoid questions about financial support having an impact on legislation.

Reached Thursday, Howard said he didn't know the contribution had been returned. "I respect that decision, but it's not going to change our process," he said.

Howard said the change in procedure was the result of a "high level of frustration by the business community" following the 2004 legislation session. "We felt we needed to build more accountability into the process," he said.

The discord is unusual for the caucus and chamber, at least publicly. The caucus was the leading force in pushing through a number of business initiatives, including lawsuit reform, during the recently completed session.

But the relationship has grown increasingly tense as GOP lawmakers say chamber officials are getting too cocky. Other political observers say that about the Republicans saying "no, thank you" to the money.

"I think it (the divide) could have a significant impact legislatively," said Chip Felkel, a political consultant who runs his own firm, The Felkel Group. "I think the business community has to be very cognizant" of the caucus' power.

Otherwise, he said, "they have to be ready for a political fight."

This is the second time this year that the caucus has returned a donation. In February, lawmakers questioned a $3,500 contribution from Claude W. Burns III, who was a candidate for an open Citadel Board of Visitors seat.