Running an empire is not cheap.

The revelation that Navy Secretary Ray Mabus has run up $4.7 million in travel expenses, over 930,000 miles, and a total of 373 days on the road in his five years in office should not surprise anyone, until one realizes that the numbers conceal as much as they reveal. As the Secretary travels by military aircraft and naval vessels, the cost of getting from point A to point B is not included, nor are a lot of the related staffing expenses as they are taken care of by Defense Department personnel who would be getting paid anyway.

Even with those sunk costs, however, managing visitors nevertheless compromises the ability of the local mission or command to carry out its normal duties. In my experience, the visit of a senior bureaucrat, a congressional delegation, or a high-ranking military officer overseas is both a money pit and a time-waster as it invariably requires weeks of preparation prior to the arrival of the potentate.

Congressmen are notorious for their worldwide travel as part of “Congressional Delegations” (CODELs), which are intended to be both “fact-finding” and “educational.” Most CODEL visits not surprisingly occur in the summer when Congress is in recess, and sometimes lack seriousness or even any recognizable agenda. Sixteen congressmen traveled to Rome in March to attend the installation of Pope Francis at a cost of $63,000, a relatively small expense by government standards, but nevertheless a gesture that should have been paid for either through a private foundation or by the congressmen themselves.

America’s legislators are also prone to travel with their families and staffs in tow, particularly when the destination is desirable. Phony agendas are frequently contrived with the cooperation of the local U.S. Embassies to permit the government to plausibly pay for the supernumeraries. This includes spouses attending the opening of a school or visiting a hospital. Generally speaking, a meeting with local officials during a CODEL is sufficient to justify the trip. That is the “fact finding” part and the rest is “educational.” CODELs traditionally traveled VIP on military aircraft to many destinations, but new post-sequester regulations now require them to travel on commercial carriers. By claiming that they have to work immediately upon arrival in a foreign destination they are able to upgrade to Business Class.

Congressmen and staffers frequently also benefit from trips arranged by lobbyists, interest groups, or even foreign governments. Sen. John McCain’s frequent maladroit appearances in international hot spots are often privately funded. In a notorious case recounted in the Washington Post, “About a dozen congressional staffers flew business class on a trip to China last summer [2012] and stayed at luxury hotels while touring the Great Wall and the Forbidden City and receiving a ‘briefing on ancient artifacts and dynasties’ at the Shanghai Museum. The all-expenses-paid visit came courtesy of China.”

And some other senior officials are even less inclined to stay at home. Hillary Clinton logged almost one million miles while visiting 111 countries during her tenure as secretary of state, and John Kerry will likely easily surpass that record having visited 51 countries and totaled over 520,000 air miles in his first year alone.

Secretaries of state travel on a specially equipped Boeing 757 and have many of the security and communications add-ons that accompany the president, including advanced Secret Service teams and supporting aircraft to carry journalists and staff. But at least Clinton and Kerry had a good excuse for their peripatetic ways: dealing with foreigners is in their job description. As for the actual costs of all the travel, those remain a state secret and would probably be misleading even if an attempt were made to break them down. As the aircraft, crew, security details, and communications staff are supplied by the government and are paid for whether they are being used or not, it is difficult to separate out discretionary costs. Hotels, meals, and entertainment expenses have not been made public for such official travel and are not accessible through the Freedom of Information Act.

Perhaps not surprisingly the greatest abuse of the taxpayer-funded travel privilege comes from the White House, which routinely under both Republicans and Democrats mixes “official” trips with fundraisers and other activities that are strictly partisan politics in a deliberate attempt to have a nod to government business pay for the politicking. President Barack Obama is indeed the “most well-traveled”  president in U.S. history and also the most expensive.

The Democratic National Committee is supposed to reimburse the government for any costs that relate to electioneering or fundraising, but Obama, like his predecessors and contrary to his pledges of “transparency in government,” has refused to reveal just how much that amounts to. It is to be presumed that infrastructure costs including $228,000 per hour for Air Force One alone are considered to be a fixed expense, as is security and ground transportation, which all suggests that the actual reimbursement might well be more notional than real, meaning that it would be embarrassing to actually reveal how little it is.

Watchdog group estimates of Obama travel, including more than $7 million spent on vacations to Hawaii and Martha’s Vineyard and an appearance on the Jay Leno show in 2013, run to over $44 million. A 13-hour cameo appearance at the Nelson Mandela funeral cost $11 million and included a bill for 127 hotel rooms.

Estimates for presidential travel costs should be considered to be minimalist as many actual expenses are picked up in other ways, including the White House operating budget, or are not included. And First Lady Michelle is also on the government dime when she travels separately. A recent “non-political” trip to China had her staying at the Westin Hotel at $8,400 per night, a suite that had been considered unacceptable for an earlier visit by Vice President Joe Biden because it was too expensive.

What arguments are made for all the traveling and the expense that is involved, a phenomenon that is unique to the U.S. government? The president represents the country in international fora and while one might disagree with the rationalizations for some of the travel, few would dispute that it is generally speaking a necessary evil. What is not necessary is the imperial entourage that accompanies the president, reported to be for some trips a second 747 for the media and other guests, three cargo planes, a total of 900 fellow travelers and staff, and a supply of armored vehicles.

For travelers from the intelligence and defense establishments there is an understanding that being briefed in Washington is not the same as visiting a field operation and seeing how things function first hand. The only problem with that argument is that the visits of senior officials and military officers are carefully orchestrated and prepared, meaning that the insights gained are carefully managed and pretty much identical to those that would be obtained from a briefer back at home without being able to look out the window and see sand dunes.

It is also sometimes argued that a visit to the field allows senior management to mix with lower ranks to obtain their views and insights, but in my 20 years of experience in government I never witnessed a situation in which congressmen or flag officers were allowed to mingle with the lower rank and file unsupervised. Secretary Mabus indeed describes a chance encounter with a junior officer in Hawaii during which she vented about her career prospects because she could not serve on a submarine. Mabus changed the rules to permit her to serve underwater, but citing the conversation as justifying his travel to Honolulu is in reality a thin justification for a lot of unnecessary expense.

A more persuasive argument is that in the context of American empire it is desirable to visit the client states to convince the local allies that they are truly respected and loved by the Mandarins in Washington. That argument has some cogency as I can recall visits to overseas posts by Congressional Delegations and senior bureaucrats that largely consisted of series of briefings and social gatherings intended not necessarily to educate or inform but rather to reinforce the bond between the two nations. It is of course difficult to calculate how much such contact is worth and impossible to say whether it is justified at a time of government-wide fiscal restraint.

What is certain is that no foreign legislature enables its elected officials to travel as intensively as the U.S. Congress. And no head of state costs as much as President Obama.

Philip Giraldi, a former CIA officer, is executive director of the Council for the National Interest.