Recent news that the General Services Administration blew more than $800,000 of taxpayer money on a 2010 “conference” that was actually an extended, over-the-top Las Vegas area party was bad enough. But congressional hearings this week have shown that the agency’s free-spending bash in the desert was, as Rep. John Mica, R-Fla., put it, “just the tip of the iceberg.”

Or to borrow another cliche, as Inspector General Brian Miller told the Senate public works panel Wednesday of serious GSA problems: “Every time we turn over a proverbial stone, we find 50 more, and we find things crawling out from under them.”

Though Mr. Miller is only looking into allegations of bribery and kickbacks within the Pacific Rim region, he warned that they might be more systemic across the GSA. Citing a famed criminal, he explained: “Willie Sutton was asked, ‘Why do you rob banks?’ He said, ‘That’s where the money is.’ Part of the reason there is a lot of crime, fraud, waste and abuse at GSA is because a lot of money flows through GSA.”

Acting Administrator Daniel Tangherlini, who took over the agency early this month when Martha Johnson resigned in the wake of the latest GSA scandal, assured senators Wednesday that new oversight measures are being implemented to prevent repetitions of the Vegas excesses.

But GSA officials have offered similar assurances after past scandals struck the agency — including contract-abuse allegations that led to the ouster of Administrator Lurita Doan four years ago.

At least Mr. Tangherlini answered lawmakers’ questions. Jeffrey Neely, acting commissioner of the GSA’s Pacific Rim region and the apparent party planner for that Vegas soiree, preferred to cite his Fifth Amendment right to remain silent on Monday.

However, squandering millions on junkets and dubious “award” programs for GSA employees isn’t all the agency has done wrong. Just last year, seven GSA staffers were found guilty of accepting bribes and defrauding the government of roughly $750,000.

And this is the agency responsible for spending huge sums of public funds while managing federal property and procuring materials and services for federal agencies.

Rep. Mica, chairman of the House Transportation and Infrastructure Committee, fairly asked colleagues and the audience during a Tuesday hearing: “How many of you would trust the GSA to manage your property?”

And how many more examples of GSA waste — and alleged fraud — will investigators find, as Inspector General Miller put it, “crawling out from under” the agency’s long-running and blatant mismanagement?

The GSA clearly needs a thorough overhaul that guarantees far more oversight. And election-year implications aside, the Obama administration should make that overdue mission a high priority.