The White House executive complex is actually composed of four buildings:
During much of the 19th century, the White House grounds and the Executive Mansion itself were quite open and unprotected. President Andrew Jackson gave unfettered access to the White House during his inauguration. Today, the State Rooms of the Executive Mansion are still open to public view, and more than 1.5 million people tour the Mansion every year. Free, public access to the White House grounds during the daytime did not end until World War II.
Visitors to the White House on business are required to report to various gates surrounding the White House complex, and only those with official appointments—who have undergone meticulous scrutiny—are admitted.
After the 1983 assault on the Marine quarters and American Embassy in Beirut, concrete barriers were installed around the White House perimeter, though these have since been replaced by a series of reinforced vertical posts. Perimeter fencing and gates have been given more reinforcement, and additional guard houses have been put up throughout the grounds since. Both the East and West Executive Avenues are closed to vehicles, and are sometimes closed to pedestrian traffic. In the 1990s, the fence around the White House was pushed outward by a block in order to make it harder for a car bomber to target the complex.
The heart of the White House's "home security system" is the people who are charged with guarding it. The Secret Service, Park Police and Washington, DC, metro police all have roles in protecting the White House, with the Secret Service being the primary entity in charge of White House security.
The Secret Service was created in 1865 as part of the Treasury Department, and interestingly enough, its main responsibility at the time was to crack down on counterfeiting. It wasn’t until 1894 that Secret Service agents were detailed to the White House for the first time, to protect President Grover Cleveland from a threatening band of gamblers from Colorado. After President William McKinley was assassinated, the Secret Service assumed full-time responsibility for the safety of the new president, Teddy Roosevelt.
While there are various types of alarms throughout the White House complex, not a lot of information is publicly available about them. In addition to the usual intrusion and fire systems, the White House also has systems in place to detect biological hazards.
One of these alarms was triggered in 2002, when then-President Bush was in China on a conference call with Vice President Cheney. Cheney informed him that bio hazard alarms in the White House had gone off. To determine if it was a real or a false alarm, security experts put mice in the area to test the air—a sort of "canary in a coal mine" situation.
A similar incident happened in October of 2001, according to Jane Mayer, a writer for The New Yorker. Both incidents proved to be false alarms.
Since 1912, there have been 30 known intrusions or attempted intrusions at the White House. The latest—and perhaps most well-known breach of White House security—took place in 2009, when Tareq and Michaele Salahi, described by The Washington Post as "polo-playing socialites from northern Virginia," crashed a state dinner after a Secret Service checkpoint failed to follow procedure to check if they were on the guest list. Secret Service Director Mark Sullivan eventually accepted blame for the breach in security.
Just as the White House has multiple layers of security, your home should use a layered protection strategy. It all starts with awareness of security and smart practices, like always locking up when leaving and not opening the doors to strangers. Physical security—in the form of high-quality locks on doors and windows—provides another layer of security.
A monitored home security system augments these basic security practices with sophisticated electronic detection of fire or intrusion, alerting homeowners and calling emergency responders when necessary.