When my family and I got in the car in Washington to drive to Cleveland for the debate last Tuesday, we carried with us pages of protocols from the Cleveland Clinic and the Commission on Presidential Debates. At the hotel, our temperatures were taken as we entered, and early the next morning we went to the Cleveland Clinic laboratory for hospital-grade nasal swab coronavirus tests — self-isolating in our hotel room until we got back negative results. We returned to the clinic for wristbands to indicate our clean results; of course, wearing masks the entire time.At every checkpoint as we walked to the debate hall, we had to show our wristbands and wear masks. Inside the hall, meticulously laid out for social-distancing with many empty seats to separate people, everybody wore masks and respected the protocols — except the Trump entourage, including family, staff and some members of Congress, such as House representative. Jim Jordan. Despite the request of Cleveland Clinic personnel, they sat in the first two rows without masks throughout the debate, and after. That, no surprise, was the subject of much discussion in the hall — well before reports on Thursday night that Hope Hicks, a close aide to the President who had been in the room, had tested positive for the coronavirus, and before the White House announced early on Friday that President Donald Trump and the First Lady had also tested positive, a month before the presidential election.As the shock waves spread, so did questions about the many tricky scenarios raised by the prospect of a president and perhaps vice-president at some point catching a powerful and deadly virus. What if one or both were incapacitated? What if one or both died before the election? What if the President were to win the election — and die right afterward? What if the winner died before the inauguration but after the electoral college met?There is no suggestion that any of this is imminent — Vice-President Mike Pence tested negative on Friday and appears to be in good health, the President’s virus symptoms have been described as mild, and Joe Biden, the former vice-president, who could have been exposed to the virus at the debate, also tested negative.But what if?Unfortunately, although it has long been clear that the country needs better answers to questions such as these, we still don’t have any.I have spent a good deal of time since 9/11 focused on the many gaps in our Constitution and law over the continuity of the presidency, Congress and the Supreme Court. The drive to Cleveland took us past the Flight 93 National Memorial, at the crash site where passengers brought down the aircraft to keep it from hitting the Capitol, its likely intended target. Congress was in its morning hours that day, with many lawmakers and staffers at the Capitol complex. A large aircraft filled with jet fuel slamming into the cast-iron dome would have killed or incapacitated hundreds of lawmakers. Congress under the Constitution cannot operate without a quorum of half its members, so we might have had no legislative branch at a time of grave national crisis, as replacements for the House can be selected only in special elections that often take months. That would mean a country operating with a form of martial law.It quickly became apparent after 9/11 that our country has no basic plan for what each of the three branches of government would do in the event of a catastrophe. So I and others established a Continuity of Government Commission that issued three reports — on Congress, presidential succession and the Supreme Court, with a road map to provide for continuity in the event of a terrorist attack, a natural disaster or a pandemic (a scenario that was raised because of the anthrax attacks after 9/11). A few lawmakers at the time from each party understood the need, but the broader response from Congress, the President and the Chief Justice ranged from indifference to hostility, and virtually nothing was done.Congressional vulnerability was again obvious when the pandemic hit. There was no procedure in place to account for circumstances when most lawmakers could not get to Washington because of illness or travel restrictions — and no quorum would mean no Congress during a health and economic disaster. With some encouragement from me and my colleague, Tom Mann, the House finally passed a measure to allow a form of remote voting and meeting. The Senate, however, has done nothing to provide for that contingency.As for the vulnerability of the executive branch, Trump’s diagnosis has highlighted the reality of presidential succession, which is that the law implementing it is flawed; there are ambiguities concerning what happens if officials die right before an election or during the transition; and the set of constitutional provisions on succession, especially the 25th Amendment, leaves one big hole.The Presidential Succession Act of 1947, the third one in the nation’s history, was enacted at the insistence of President Harry Truman. The original succession act named only two successors after the President and the Vice-President: the president pro tempore of the Senate and the Speaker of the House. More than once in the 19th century, when presidents died in office and Congress was not in session, there was no one in line once the Vice-President assumed the office. That precipitated a new act in 1886, which took the lawmakers out and added the members of the Cabinet in order of creation of the offices, putting the Secretary of State after the Vice-President, then the Treasury Secretary and so on. Truman wanted elected officials back in, so the 1947 law put the speaker next in line after the Vice-President, then the president pro tempore of the Senate, and then the Cabinet members. But there was still no way to replace a vice-president if the President died in office; it took the assassination of President John F. Kennedy to spur the 25th Amendment.On 9/11, all those in the line of succession were based in Washington, increasing vulnerability if there were a devastating attack on the capital. And there are real concerns about having members of Congress in the line, including the prospect of having someone from the opposite party assume the presidency — with a conflict of interest for the speaker in the event of presidential impeachment. The 1947 law also has a curious “bumping” provision, by which a Speaker of the House who does not take the slot can at any time bump a Cabinet member who has assumed the office.The 25th Amendment has its own gap that would be relevant if Pence were to contract the coronavirus while Trump has it and if either man’s health worsened. While the amendment provides for replacing the Vice-President and dealing with a presidential disability, it does not have an answer if both the President and the Vice-President are incapacitated. The Presidential Succession Act is triggered by the deaths of the President and Vice-President. There is no path in law or the Constitution to determine who has presidential authority if both are, say, on ventilators. We could have Secretary of State Mike Pompeo jump up and proclaim, “I’m in charge!” And Mark Meadows could respond, “No, I’m the White House chief of staff, I’ll make the decisions.”Foreign actors, meanwhile, would ponder the power struggle and lack of command chain.The election poses significant questions, too. Most states have printed their ballots, and more than one million people have already voted. If a candidate were to die in October, there is no chance that ballots could be changed, even if the party chose a successor. Congress could pass a law postponing the election, but that would raise more complications, given the need to get everything done — including states certifying electors, electors meeting and Congress certifying the results — before the constitutional deadline of noon on January 20 to swear in a president. If the election went forward, what would electors do? The Supreme Court ruled in Chiafalo v Washington in July that electors can be bound, but the opinion noted in a footnote that the restriction would not apply in a case such as this. And what if some electors split their votes, some choosing the Vice-President, others sticking with the deceased president, leaving the answer to the House?The possibilities are dizzying. There are some answers in the laws, but there is a lot of fog. Of course, it is nearly impossible to game out every scenario and plan for them. But the brutal reality is that, despite warnings after the tragedy 19 years ago, and insistent calls since to grapple with these issues, our government closed its eyes and ears to the dilemmas and left us to scramble for answers now. We have to hope that the challenges remain theoretical.• Norman Ornstein, a resident scholar at the American Enterprise Institute, is a coauthor of One Nation After Trump: A Guide for the Perplexed, the Disillusioned, the Desperate, and the Not-Yet Deported