A New York City parks department official took the upcoming mayoral election into account in denying permission for a concert of John Lennon’s music last year on Central Park’s Great Lawn.

An e-mail from the Parks and Recreation Department’s head marketing officer, Elizabeth Smith, said, “This event does look great but we had to admit that it was going to be difficult, right after all our problems with the rally requests for the park, and right before Mike’s re-election (this is for Oct 05) that this is likely to happen on the Great Lawn.”

The e-mail surfaced as part of the discovery process in a court case brought by the National Council of Arab Americans, one of several groups who were denied permission to use the Great Lawn for a rally during the 2004 Republican National Convention.

It offers an unusual look at how politics factored into a decision by an agency in the Bloomberg administration, which prides itself on making decisions on the merits, not politics. The concern appeared to be that if the department granted permission for a musical concert but not to political protesters, Mr. Bloomberg’s claim that his denial of the protest permits was based on concern for the well-being of the park’s turf would be proven false, and that it would hurt him politically.

Spokesmen for the mayor and the parks department referred calls for comment to the city’s law department.

Through a spokeswoman, the city’s attorney on the case, Robin Binder, said: “Due to pending litigation we cannot discuss the case.”

A lawyer for the National Council of Arab Americans, Carl Messineo, said that two years after the Republican National Convention, the group is in court seeking “an acknowledgment that what happened is unconstitutional.”

The Arab group is also asking the judge, William Pauley III of U.S. District Court in Manhattan, to declare unconstitutional the Parks Department’s newest policy of permitting only six large-scale events on the Great Lawn each year.

Mr. Messineo said the documents support his claim that the parks department and the mayor acted in an unconstitutional manner when they decided that there would be no rallies on the Great Lawn during the convention.

“The Parks Department issuance and denial of permits functioned with the unfettered discretion of a Jim Crow era sheriff’s office,” he wrote this year to the judge.

Internal e-mails suggest that parks department officials, with Mayor Bloomberg’s support, had decided in the spring of 2004 to keep rallies off the Great Lawn. The 13-acre Great Lawn has annually hosted the New York Philharmonic and Metropolitan Opera and has also been the site of large-scale rallies in the past several decades.

But the question that lawyers have spent some time debating is whether that decision was made to prevent high-profile political rallies while the convention occurred or simply to protect the grass from being stampeded underfoot.

One e-mail, now on the court record, refers to a March 23, 2004 meeting between Parks Commissioner Adrian Benepe and Mayor Bloomberg “regarding the RNC rally permit requests.”

Written by then-Parks Department employee, Laura Gaul, to Mr. Benepe, the e-mail appears to be a draft of an internal parks department memorandum.

“As Adrian previously emailed you, today’s meeting with the Mayor went quite well,” the e-mail reads. “We are thrilled that he supported the idea of not having any rallies on lawns in parks and are happy to have them located in paved areas (as we’ve suggested to have the Arab American rally in Foley Square).”

In his response to the message, Mr. Benepe suggests: “please tone down the mtg with the mayor.”

In a two page affidavit that Mr. Bloomberg signed in May 2005, he wrote that he backed a Parks Department decision from March 2004 to deny a rally permit to a separate group of protesters also hoping to use the Great Lawn during the convention. He writes: “I understood that a Parks Department permit was going to be denied because a rally of that size could severely damage the Great Lawn, which was restored several years ago and is no longer suitable for events of this magnitude.”

Before it was landscaped in the mid 1990s at a cost of $18 million, the Great Lawn was sometimes referred to in the 1980s as a “the Dust Bowl.” But Mr. Messineo said concern over the state of the grass is simply a cover.

“The true reason for the denial was never acknowledged — That the city had a de facto ban on political protest rallies on the Great Lawn,” Mr. Messineo writes in a court filing this year. “The Mayor, a key political and financial supporter of the Republican National Convention approved in March, 2004 the Park Department’s plan to ban protests from the Great Lawn during the Republican National Convention period.”

In an effort to prove this point, the plaintiffs have turned their focus to proving that a rally of about 75,000 persons — the number of people that the National Coalition of Arab Americans expected to turn-up — would not have destroyed the lawn.

In a series of depositions taken this year, various parks department officials and outside experts, including a Cornell professor who studies turf grass management, Anthony Martin Petrovic, have debated the finer points of grass care.

A motion for summary judgment in the case is currently pending before Judge Pauley.