(This post has been updated.)

Sen. Claire McCaskill lit into a State Department official Tuesday when he was unable to answer a series of questions about the cost of a training facility for U.S. diplomats that the department has long sought.

McCaskill asked Assistant Secretary of State for Diplomatic Security Gregory Starr how much “hard skills” training, which is currently done at 11 different leased locations, costs now. He didn’t have that figure.

“You came to this hearing and you don’t know that number? Seriously?” the Missouri Democrat said, voice raised, at a Senate Homeland Security Committee hearing on the training facility costs.

She then asked how many weeks of training is needed each year. He couldn’t answer that specifically either.

“You don’t even know how many weeks of training you need at this hearing?” she asked, putting her head in her hands.

As the Loop has reported, there is an ongoing struggle over whether State should build a new facility known as the Foreign Affairs Security Training Center (FASTC), on the Fort Pickett military base in Virginia, or retrofit an existing training site for federal law enforcement in Glynco, Ga., called the Federal Law Enforcement Training Center (FLETC), operated by the Homeland Security Department.

McCaskill accused Starr of not making a business decision in the taxpayer’s interest, but merely that State wanted its own facility and made it happen.

Starr said a Government Accountability Office report analyzing the two projects, due sometime in the next month, will confirm that in the long run the Virginia project is more cost effective than transporting diplomats back and forth to Georgia.

In early 2014 it looked like the White House was going to scrap State’s plans for a multimillion-dollar, brand new diplomatic security training facility. Its budget analysts decided that the Georgia site was the cheaper option.

But then Deputy Secretary of State Heather Higginbottom got involved.

Higginbottom, previously deputy director of the Office of Management and Budget, reached out to her former OMB colleague, Steve Kosiak, who oversaw the national security and defense budget.

Soon thereafter, OMB changed its mind.

According to an OMB analysis and e-mails between Higginbottom and Kosiak, the White House initially decided expanding the Georgia location made more economic sense, according to documents obtained by the Loop.

“FLETC can meet the vast majority of State’s current requirements for access to facilities and course scheduling, training requirements, and life support services, all at a much lower estimated cost than Fort Pickett,” according to a late 2013 OMB cost analysis.

“While Fort Pickett would have an advantage for location and interagency synergies, the [OMB’s resource management office] does not believe that the difference is substantial enough to rule out FLETC… FASTC at FLETC would ultimately have more capabilities than FASTC at Fort Pickett at a lower cost.”

Higginbottom wrote to Kosiak wanting to discuss State’s “appeal” of that decision. Kosiak responded that he didn’t understand State’s “reluctance to consider FLETC.” They met in February 2014 and FASTC was suddenly back on track.

State sent a letter to the House Foreign Affairs Committee in October 2014 stating that OMB endorsed its Virginia plan as the “most effective and efficient” choice. But committee staff had heard differently from some OMB officials who remembered the initial analysis.

At Tuesday’s hearing, acting OMB Deputy Director for Management David Mader said the agency ultimately deferred to State to know what was best for its security needs. He said the administration believes the Virginia project “strikes the right balance” between cost and security.

State’s proposal would cost approximately $413 million, which is a dramatically scaled back version of an original $1 billion plan. FLETC claims it could develop the same facility for half that.

Yet, despite the cheaper construction price tag, State argues that the money spent flying diplomats and their spouses to Georgia for hard skills security training would eventually surpass the savings. Plus, it’s less efficient since much of their soft skills training occurs in Washington and Virginia.

State also contends that the Virginia site allows the diplomats to train alongside Marines at Quantico, who serve as embassy security.

The issue is as much a battle between a few members of Congress and State, as it is a regional one between Virginia and Georgia lawmakers who want the project in their back yard. Lawmakers have sought language to freeze additional funding for the project until there’s more analysis of the costs.

But McCaskill went even further, saying she wanted “to stop this dead in its tracks.”

After the hearing she apologized privately to Starr for “yelling.” But said, “I need numbers.”