The news that an aide to Brazilian President Jair Bolsonaro, who met with President Trump just days ago at Trump’s Mar-a-Lago resort, had tested positive for covid-19 makes it all the more inexplicable that the White House says the U.S. president has not been tested for the disease.

The Brazilian government says that news reports Friday that Bolsonaro had tested positive for the new coronavirus were false, and that his test came back negative.

Any delay in testing Trump is clearly not because the Secret Service, White House medical personnel or the White House Military Office ignores biological threats; the White House actually is kept pressurized, so that it’s impossible for airborne biological or chemical threats to enter the building. Instead, the president’s seemingly laissez faire attitude toward testing most likely reflects both the difficult political environment he faces and a surprising truth about our government’s continuity planning.

Assuming that the White House is telling the truth — which is never a safe assumption with an administration and a president that has turned outright lies into a daily art form — and Trump really hasn’t been tested, there are almost certainly at least four major factors figuring into the decision.

First, despite being a renowned germophobe, Donald Trump clearly has had his head in the sand about the potential danger of the new coronavirus that’s sweeping the globe — to himself, the country or the world. He’s been so blasé about the pandemic that even his favorite Fox News host, Tucker Carlson, took him to task this week for playing down the severity of the threat. Why test for something you’re not worried about? As Trump said Thursday: “It’s going away. We want it to go away with very, very few deaths.”

Second, and most simply, given the national shortage of available tests, the administration may be simply trying to follow its own advice: While many other countries are testing thousands or even tens of thousands of people per day, the United States is strictly rationing coronavirus tests, and current policy says that there’s no need to test people who don’t have symptoms. “There is currently no indication to test patients without symptoms, and only people with prolonged close exposure to confirmed positive cases should self-quarantine,” White House press secretary Stephanie Grisham told reporters this week.

Third, the government would face several bad scenarios the moment it announces that the president has been tested — including injecting more uncertainty into stock markets and geopolitical conversations during the hours that it takes to get results from the test. And if Trump had indeed been infected with the virus, that would bring much more serious uncertainty.

The fourth factor, though, might be the most surprising to most Americans. I’ve spent years studying the nation’s worst-case scenario planning — a series of interlocking and mostly highly secret plans known as Continuity of Operations (COOP), Continuity of Government (COG) and Enduring Constitutional Government (ECG) — and here’s the surprising takeaway: Most U.S. government plans assume the elected president doesn’t survive a true catastrophe.

The hard truth is that the nation’s continuity planning simply doesn’t value the “elected president” all that much; most COG scenarios through the Cold War and the Global War on Terror start with the premise that the president is expendable and, in fact, almost certainly dies at the outset of a major crisis. Instead, the emphasis in contingency planning focuses on protecting the “Office of the President,” the much broader line of presidential successors outlined in the 25th Amendment, what’s known as “Continuity of the Presidency” (COP). The system is aimed less at ensuring the survival of “the” president than ensuring the survival of “a” president, ensuring that someone in the line of the succession is able to assume the presidency at a moment’s notice; the president may die, but the presidency shall live.

Through the Cold War, presidents long recognized this truth; chief executives from Harry Truman to Jimmy Carter understood that they would most likely die in the opening minutes of a surprise attack and that it would be up to their successors to carry on the business of the nation.

That sense was only reinforced in the post-Cold War era. After the Oklahoma City bombing and the sarin gas attacks on the Tokyo subway by a doomsday cult in the 1990s, the United States, which had long planned to evacuate leaders from Washington in an emergency, began to prioritize keeping COG systems running round-the-clock regardless of the threat. As Richard Clarke, who headed contingency planning in the Clinton administration, told me during my book research, “It’s fine to have a bunker in the mountains, but there’s no one there on a daily basis, so in a surprise attack, it’s useless.”

Similarly, the surprise of the 9/11 attacks underscored that the government needed plans to “devolve” power from the capital to existing facilities and existing personnel permanently located outside the capital.

The Federal Emergency Management Agency — the agency best known for its response to natural disasters — actually traces its roots to the nation’s nuclear war response manager, and it’s still in charge of our doomsday plans today; its Central Locator System has long tracked the whereabouts of all the presidential successors (the system is now called the Internet Protocol Locator) so that it will know at any given moment the highest-ranking survivor in the line of succession.

And yet even under these long-established planning assumptions, the behavior of the Trump administration puzzles, as it continues to demonstrate a severe lack of urgency in basic protective measures. The U.S. government should be practicing continuity-related “social distancing” measures within itself. The signs that true “continuity of government” measures haven’t kicked in are all too evident in the images coming out of the White House every day. Trump dove into a crowd of supporters at the Orlando airport Monday to shake hands after disembarking from Air Force One, and Mar-a-Lago still plans to hold events even as authorities ask people not to gather in large groups.

After 9/11, the fear of follow-on attacks led to Vice President Richard B. Cheney’s self-banishment to “undisclosed locations” around the country, ranging from extended fishing trips to nights at Camp David. Why isn’t Vice President Pence physically separated from the president or even removed from Washington? Just within the past week of this public health crisis, it’s become clear that senior government leaders from various branches of government have faced potential exposure from conference appearances at CPAC and AIPAC, as well as in day-to-day business.

With a fast-moving virus that appears to hit older people particularly hard, it’s a recipe for trouble when the 73-year-old president and 60-year-old vice president appear in public together, along with the nation’s top medical leaders (National Institute of Allergy and Infectious Diseases head Anthony Fauci is 79; Centers for Disease Control and Prevention director Robert Redfield is 68). Perhaps it’s time for our government officials to start taking social distancing seriously, too.