Live coverage was a long time coming. as much as the government loves to spy on us.. they really didn't want us to keep an eye on them. The U.S. House of Representatives Clerks office summarizes that angle on history thusly:
The first live television broadcast coverage of a congressional proceeding occurred on January 3, 1947, when cameras were allowed into the House Chamber to telecast the opening of the 80th Congress. It also was the last such broadcast for more than three decades, despite the fact that television became a major cultural phenomenon... At first, Congress utilized the new technology sparingly. In the House Chamber, cameras occasionally telecast major speeches... but by 1952 they were banned not only from regular floor sessions but in committee hearings as well.After Watergate they needed to clean up their act. In March of 1977 Speaker Thomas “Tip” O'Neill [D] Massachusetts decided to go for a 3 month trial period. The first 3 months went fairly well and the test ended after a 6-month run. H. Res. 866 passed by a vote of 342 to 44 on October 27, 1977 and they spend 1.2 million dollars on a studio and 6 cameras. The system was launched officially march 19th 1979, PBS and C-SPAN were the first networks to use the feed.But while the big formal launch was in March of 79, and the "test" ended September 1977... there were still live broadcasts in between with one very notable oops. Tip O'Neil had been warning the reps that they were live on air for months trying to drill it into their heads that people could hear them. On Tuesday August 15th 1978 their first recorded faux pas. Mr. Ronald Dellums [D] California stated that his fellow representatives are "slightly intoxicated." O'Neil, on his way to D.C. at the time heard the remark broadcast on the radio repeatedly and was less than thrilled.
Despite the flub, on March 19, 1979, public television and the C-SPAN network, tapping into the House television system, began regular live broadcasts of floor proceedings. In 1986 the Senate got over their stage fright and followed suit. This was all of course before C-Span bought WDCU from the District of Columbia and launched 90.1 WCSP in the heart of D.C. carrying unedited senate and house coverage anytime they want to.