Al Drago / Getty Images The American flag flies at half-staff as inauguration construction continues on the west front of the US Capitol on Jan. 9. The proceedings that will take place on the morning of Jan. 20, in public view on the west front of the United States Capitol, just steps from the insurrection that killed five people, endangered Congress and the vice president, and led to the resignation of the Capitol Police chief, amount to what is known in Washington, DC, as a “National Special Security Event." You will hear a lot more about National Special Security Events, aka NSSEs, in the next eight days. Joe Biden’s inaugural officials, eager to allay security concerns after President Donald Trump’s supporters broke into the Capitol last Wednesday, tick off the letters in quick succession, N-S-S-E, in conversations about the implications of the acronym. In many cases, NSSEs can take more than a year to plan. When something is an NSSE, it means that multiple federal agencies are involved — not just the local police and fire department, though they are as well, but the United States Secret Service (which serves as the lead agency), the Department of Defense, the FBI, the Department of Health and Human Services, and the Federal Emergency Management Agency. Officially, there have been fewer than 75 NSSEs in the history of the United States. NSSEs are not events so much as occurrences of great national interest, identified at the discretion of the sitting secretary of Homeland Security: the visit of Pope Francis, the Olympic Games in Salt Lake City, certain Super Bowls, the funeral of Ronald Reagan, G8 summits, and every inauguration since President Bill Clinton created the NSSE designation in 1998 as part of a security framework for marshaling “the full protective and consequence management capabilities of the Federal Government.”