ON FRIDAY, Mitt Romney — along with an entourage of his most important donors and fundraisers — arrived at the tony Utah ski resort of Deer Valley. Whether the presumptive presidential nominee or his 700 close friends at this so-called Republicanpalooza are aware that the Works Progress Administration built the resort’s first ski trails in the mid-1930s is not known. Unfortunately, also unknown to most Americans are the identities of the “bundlers” present at this weekend fete, the fundraisers largely responsible for Mr. Romney’s unexpected outraising of President Obamain May.

Campaign finance laws don’t require candidates to release the names of their bundlers, except in the case of registered federal lobbyists. But the Romney campaign’s refusal to identify those who bring in a quarter-million dollars or more differentiates it not only from the Obama campaign but also from those of the past two Republican contenders for the White House, President George W. Bush and Sen. John McCain (Ariz.). Both released lists of their major fundraisers, along with the scale of their harvests.

In Mr. Romney’s case, big contributors have played an especially important role. In May, for instance, only 15 percent of donations were smaller than $200; the rest of the $76.8 million his campaign tallied in conjunction with the Republican National Committee was clearly bolstered by these bundlers and their connections. Why will Mr. Romney not disclose the names of these supporters to whom he’s most indebted? What is there to hide?

As for the weekend in Utah, the bundlers — whomever they may be — are certainly in for a treat. Some of the most luminous personalities in the Republican stratosphere are expected to attend, including former Florida governor Jeb Bush, former secretary of state Condoleezza Rice and George W. Bush strategist Karl Rove. As The Post reported this week, potential Romney running mates such as Louisiana Gov. Bobby Jindal, Sen. John Thune (S.D.) and Rep. Paul Ryan (Wis.) are also likely to attend.

On the agenda is a cookout with a speech by Mr. Romney and, on Sunday, a round of golf. Maybe Ann Romney will serve some of her special homemade cookies, reported to have been so successful at donor gatherings.

Selling access has become nearly universal in political campaigns. Seeking to do so in secret sets Mr. Romney apart.