During presidential election campaigns in the United States, it has become customary for the candidates to engage in a debate. The topics discussed in the debate are often the most controversial issues of the time, and arguably elections have been nearly decided by these debates. Candidate debates are not constitutionally mandated, but they are now considered an intrinsic part of the election process. The debates are targeted mainly at undecided voters; those who tend not to be partial to any political ideology or party.Presidential debates are held late in the election cycle, after the political parties have nominated their candidates. The candidates meet in a large hall, often at a university, before an audience of citizens. The formats of the debates have varied, with questions sometimes posed from one or more journalist moderators and in other cases members of the audience. The debate formats established during the 1988 through 2000 campaigns were governed in detail by secret memoranda of understanding (MOU) between the two major candidates; the MOU for the 2004 debates was, unlike the earlier agreements, jointly released to the public by the participants.

Debates have been broadcast live on television, radio, and in recent years, the web. The first debate for the 1960 election drew over 66 million viewers out of a population of 179 million, making it one of the most-watched broadcasts in U.S. television history. The 1980 debates drew 80 million viewers out of a population of 226 million. Recent debates have drawn smaller audiences, ranging from 46 million for the first 2000 debate to a high of over 67 million for the first debate in 2012. A record-breaking audience of over 84 million people watched the first 2016 presidential debate between Donald Trump and Hillary Clinton, a number that does not reflect online streaming.



Television, sometimes shortened to TV or telly, is a telecommunication medium used for transmitting moving images in black-and-white or in color, and in two or three dimensions and sound. The term can refer to a television set, a television show, or the medium of television transmission. Television is a mass medium for advertising, entertainment, news, and sports.

Television became available in crude experimental forms in the late 1920s, but it would still be several years before the new technology would be marketed to consumers. After World War II, an improved form of black-and-white television broadcasting became popular in the United Kingdom and United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in the U.S. and most other developed countries.

The availability of various types of archival storage media such as Betamax and VHS tapes, high-capacity hard disk drives, DVDs, flash drives, high-definition Blu-ray Discs, and cloud digital video recorders has enabled viewers to watch pre-recorded material—such as movies—at home on their own time schedule. For many reasons, especially the convenience of remote retrieval, the storage of television and video programming now also occurs on the cloud (such as the video on demand service by Netflix). At the end of the first decade of the 2000s, digital television transmissions greatly increased in popularity. Another development was the move from standard-definition television (SDTV) (576i, with 576 interlaced lines of resolution and 480i) to high-definition television (HDTV), which provides a resolution that is substantially higher. HDTV may be transmitted in different formats: 1080p, 1080i and 720p. Since 2010, with the invention of smart television, Internet television has increased the availability of television programs and movies via the Internet through streaming video services such as Netflix, Amazon Prime Video, iPlayer and Hulu.

In 2013, 79% of the world's households owned a television set. The replacement of earlier cathode ray tube (CRT) screen displays with compact, energy-efficient, flat-panel alternative technologies such as LCDs (both fluorescent-backlit and LED), OLED displays, and plasma displays was a hardware revolution that began with computer monitors in the late 1990s. Most television sets sold in the 2000s were flat-panel, mainly LEDs. Major manufacturers announced the discontinuation of CRT, DLP, plasma, and even fluorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are expected to be gradually replaced by OLEDs. Also, major manufacturers have announced that they will increasingly produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s.Television signals were initially distributed only as terrestrial television using high-powered radio-frequency television transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by coaxial cable or optical fiber, satellite systems and, since the 2000s via the Internet. Until the early 2000s, these were transmitted as analog signals, but a transition to digital television was expected to be completed worldwide by the late 2010s. A standard television set consists of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is correctly called a video monitor rather than a television.