* Spending culture “seeped into our national party”

* Mahoney is latest to leave Republican National Committee

* Questions surround chairman Steele (Adds Republican National Committee comment)

WASHINGTON, April 6 (Reuters) - A top Republican resigned from his party’s governing body on Tuesday, deepening a controversy around party chairman Michael Steele as Republicans try to focus on U.S. congressional elections in November.

Sean Mahoney, a member of the Republican National Committee from New Hampshire, quit in a letter to Steele, the latest fallout after revelations that a party organizer billed the RNC for $2,000 spent at a sex-themed club in Los Angeles.

Mahoney denounced the “out-of-touch, free-spending culture of Washington” that he said dominates Congress and said “the same mentality has seeped into our national party.”

“Let me be clear so that there is no misunderstanding,” Mahoney wrote. “I don’t care if the $2,000 was spent in February at a strip club or a pizza parlor. This is a matter of principle. That $2,000 should have been used to promote our conservative ideals.”

Mahoney’s resignation followed a shakeup at the RNC on Monday in which chief of staff Ken McKay became the highest official to leave since the nightclub scandal erupted.

Steele has generated questions about his leadership of the RNC, which is supposed to recruit candidates, raise money for campaigns and prepare the party for elections.

The problems come as Republicans seek to bounce back after election drubbings by the Democrats in 2006 and 2008. Republicans appear poised to make gains in November’s elections in which all 435 seats in the House of Representatives and more than a third of the 100-seat Senate are up for grabs.

In a statement, the RNC thanked Mahoney for his service and said he was among many Americans concerned about “binge spending in Washington.”

“The RNC is committed to ensuring that every donor dollar goes to building the infrastructure needed to elect conservative candidates that believe in the fundamental principles of our party,” said party spokeswoman Katie Wright.

Steele has been criticized as an attention-seeker too fond of appearing in television interviews instead of focusing on the core duties of organizing and raising money.

While many Republicans would like Steele to leave, some expect him to hang on until after the November elections -- but possibly not much longer.

The next election for RNC chairman is in January. The winner will guide the party through the 2012 election, in which Republicans will seek to stop President Barack Obama, a Democrat, from winning a second term.

Steele “never understood the role of the national chairman,” said Republican strategist Scott Reed.

“This pattern of behavior has finally caught up with him,” Reed said. “He’s about guaranteed that he won’t be re-elected, especially during a presidential cycle where the national chairman has to run a national convention, raise money and work with the Republican nominee.” (Editing by David Alexander and John O’Callaghan)