“I think we’re past that,” said Alan Patricof, a longtime donor to Mrs. Clinton, when asked about the need to lie low during the primaries.

In Philadelphia, donors were handed preferred suites at the Ritz-Carlton and “Friends and Family” packages created for longtime Clinton hands — some of them also longtime benefactors. Some were granted time backstage or in the Clinton family box with former President Bill Clinton and Chelsea Clinton. Blackstone, the private equity giant, scheduled a reception at the Barnes Foundation on Thursday with its president, Hamilton E. James, one of the leading Wall Street contenders for an economic policy post in a future Clinton administration.

The Philadelphia convention offered other symbolic contrasts to the party’s last two gatherings, when President Obama sought, with mixed success, to restrict his party from raising money to pay for the conventions from lobbyists or political action funds. Those shackles were thrown off this year, waving a green flag to Washington’s influence industry. Lobbyists and corporate representatives flooded the city, where much of the Democratic Party’s elite — and potential senior members of a future presidential administration — had gathered.

The railway giant CSX brought in old railroad cars for a reception led by Rodney E. Slater, the former United States transportation secretary turned lobbyist, who also headlined a panel on transportation policy in a future Clinton administration. At the Loews Hotel bar on Tuesday night, old Clinton hands, some now working as lobbyists, caught up with Gov. Terry McAuliffe of Virginia, a longtime family friend and one of the party’s most prolific fund-raisers.

At a private luncheon on Wednesday at El Vez, a Mexican restaurant, over a dozen Democratic governors mingled with representatives from a host of labor unions and companies, among them the Apollo Education Group, an operator of for-profit colleges that has faced a series of state and federal investigations into allegations of shady recruiting, deceptive advertising and questionable financial aid practices.