Purchase of half-hour blocs of network time by presidential campaigns goes back to the early days of television. Richard Nixon's famous Checkers speech, which saved his place on the 1952 GOP ticket, was actually a half-hour commercial, paid for by the Republican National Committe.
Adlai Stevenson, the Democratic nominee, also bought half-hour blocs during 1952 to televise campaign speeches — a tactic that failed because the live speeches were often cut off in mid-sentence as Stevenson talked past the cutoff mark.
The launch of Ronald Reagan's political career was a half-hour network speech paid for by Goldwater supporters near the end of the 1964 campaign.
But as the media market has fragmented over the past 15 years, network television has fallen from favor as a political advertising vehicle. Before Obama's announcement, the last candidate to have purchased a half-hour bloc was Ross Perot during his independent run for the presidency in 1992.
Candidates instead tend to focus their ads more narrowly, focusing on key states or communities — though Hillary Clinton's campaign did buy time for a speech on the cable Hallmark Channel during the primaries earlier this year.
Television executives, advertising experts and political analysts said the purchase of the network time — which they estimate cost $1 million or more per network — was more a reflection of the Obama campaign's brimming bank accounts than a carefully thought-out strategy.
"When you've got it, like Obama does, you'd absolutely be stupid not to spend it," said University of Virginia political scientist Larry Sabato. "It's really to pump up the base: 'We're inches from the goal line. We can feel it. Don't let up now!' ''
Evan Tracey, president of the Arlington, Va.-based Campaign Media Analysis Group, a media research firm specialzing in politics, added: "If you needed more evidence that Obama has more money than there is TV time left to buy, here it is. They're looking at the dollars in the bank, the days on the calendar, and wondering, What else can we do?' ''
Tracey said the network buy was a startlingly old-school tactic by a cutting-edge campaign.
"This is a different media environment, even from when Perot did it," Tracey said. There are a lot more channels of communication open beteween candidates and voters now. He's really folding back into one of the older ones."
But, he added, why not?
"On Madison Avenue, they like to say, Half of all advertising is wasted, you just can't figure out which half.' '' Tracey said. "In politics, it's more like 95 percent is wasted and they just don't care. If the 5 percent that's useful hits the 3 percent of undecided voters, it's well worth it."