While Democrats have denounced the GSA spending — White House spokesman Jay Carney said last week the president "was outraged by the excessive spending, questionable dealings with contractors and disregard for taxpayer dollars" — they've also quietly suggested Issa's hearing is politically motivated.

A Democratic staffer noted that Issa did not ask any GSA officials from the Bush administration — when costs for the conferences rose at an even more dramatic rate — to testify, despite having pledged to investigate both administrations equally. Spending on the conference rose from $93,000 in former President George W. Bush's first term to $655,000 in 2008, while the controversial amount in 2010 under President Obama only represented a 28 percent increase.

Issa's hearing will also be the second House probe and fourth congressional inquiry into the conference. Rep. John Mica (R-Fla.) said last week that the House Transportation and Infrastructure Committee, which he chairs, would be investigating the meeting. Sen. Dick DurbinRichard (Dick) Joseph DurbinSenate Dems set to take aim at new Trump attorney general pick Republicans seek to temper fallout from latest Russia bombshells Dem demands 'ironclad assurances' from Barr on Mueller investigation ahead of confirmation hearings MORE (D-Ill.) has promised a similar inquiry in the Senate, where both the Environment and Public Works and Appropriations committees have hearings scheduled.

But Issa's office pushed back, noting that there was a difference between increased spending under the Bush administration — which could have been justified for a number of reasons — and the concrete examples of waste found at the Las Vegas meeting.

“The Oversight Committee certainly views wasteful spending as a problem that transcends administrations and, by working to expose it, can help direct Congress toward necessary cuts to spending on the bureaucracy," said Issa spokesman Frederick Hill.

There should be plenty for the committee to discuss at next Monday's hearings. In addition to the inspector general's report, Issa's office has unearthed and distributed two videos, made at taxpayer expense, filmed by GSA employees for the conference.

One video showed employees rapping to the tune of Travie McCoy's pop hit "Billionaire."

In the film, a GSA employee mocks other federal agencies for not being able to afford flat-screen televisions and new cars and brags about avoiding investigation into the spending. At another point, Deputy Commissioner of the Public Building Service David Foley jokes about a party in a hotel suite.

Another video shows employees of the federal agency joke that their environmentally friendly initiatives were intended to earn the president good press.

In the video, office workers are shown singing about green initiatives in various scenes staged around the GSA office.

"POTUS wants a press event, a project he can show … are you ready for a miracle? GSA is going green," employees sing while seated around a conference table, waving a framed picture of the president. Some are shown wearing costumes or intentionally ridiculous accessories, like a rainbow sombrero.

After the movie, footage from the conference is shown, where convention organizer Jeffrey Neely jokes, "That was amazing, was there anybody in Region 7 who wasn’t in that thing?"

A GSA employee is then shown saying that almost everyone who worked the Friday the video was filmed made an appearance, drawing laughter from the crowd.