The $35,800 per-plate tab to attend a private fundraising dinner with Vice President Joe Biden in Charleston may sound like an arbitrary number, but there's a mathematical reason for it.

It's a combination of two of this year's campaign donation limits.

For example, the Federal Election Commission says the cash limit that an individual can give candidates this year is $2,500 per election cycle, including a primary and general election.

Combine that number, or see it as donations made by a husband-and-wife pair giving $2,500 each, it becomes a $5,000 campaign donation.

Add to that the limit that someone can give to a political party's national committee, set at $30,800 in a calendar year, and it comes out to the $35,800 limit.

Similar amounts have been recorded around the nation this year, as the Obama-Biden team assembles its war chest for the 2012 election season.

Meanwhile, it could be weeks before Democrats have to disclose the names of the 10 people who attended Thursday's fundraiser, held in a closed room in the Charleston Place Hotel, where crab cakes and filet were on the menu.

The Obama 2012 re-election campaign and the Democratic National Committee, which benefitted from the event, have until Oct. 15 to file their donor paperwork from the dinner.

Even then, the official guest list isn't required to be part of their disclosure since party committees don't have to list who sat down with the vice president, only the identities of donors and the amounts of their gifts.

S.C. Democratic Party Chairman Dick Harpootlian was the only person who attended Thursday's gathering and agreed to talk about it afterward. Harpootlian, who brought along his wife, called the meal "normal South Carolina fundraising fare." A representative of the hotel declined to discuss the menu, calling the gathering a private function.

Thursday's visit did not sit well with everyone in Charleston, including Interstate 26 drivers who reported being inconvenienced twice when Biden's motorcade traveled between the airport and downtown, once during the afternoon rush hour and again later that evening.

"I wish you and he could have seen the anger on the faces of the middle class our president claims to be championing as we sat in traffic watching a parade-length cavalcade of police officers whip by," Laura Webster of Ladson said Friday.

"Imagine getting home 15 to 20 minutes late for dinner and finding the reason for the delay to be that our vice president was collecting $35,000 each from 10 of Charleston's elite," she added. "Since none of them have blue collar jobs, why couldn't they have blocked our streets at some time other than rush hour?"

The tab to cover the vice president's three-hour stop in Charleston also has to be calculated, but it is likely to be picked up by campaign money. The FEC says that for any trip that is entirely campaign-related, the cost is treated as "a qualified campaign expense."

Biden is not known to have conducted any public business during his time on the ground.

Reach Schuyler Kropf at 937-5551.