Poll: Charting 'Convention Bounce'

N E W   Y O R K, July 25 -- What goes up does not always come down.

That’s the charm of the “convention bounce,” the jump in support that customarily accompanies a presidential candidate’s nominating convention. Sometimes it’s a short-term thing, with the race quickly returning to form. But it can be a more profound event — a coalescing of public preferences that charts the course for the remaining campaign.

So it was in 1992, the Year of the Big Bounce. Bill Clinton went into the Democratic Convention one point behind George Bush — and left it 29 points ahead. Skeptics scoffed, calling it momentary. But it lasted, and from then to Election Day, Clinton never trailed.

Bush did respond with a sizable bounce of his own. He trailed by 21 points on the eve of his 1992 convention, then moved to within five after it. But what counts is not just the bounce’s size, but its durability. In Bush’s case it didn’t hold: A week later he was back to a 19-point deficit.

Frequent Phenomenon

While no convention bounce has matched Clinton’s in 1992, many are impressive. In 1976, Jimmy Carter’s bounce to a 33-point lead underscored Gerald Ford’s weakness. In 1980, Carter bounced from a 16-point deficit to a one-point lead. (It didn’t last.) In 1984, Walter Mondale bounced from a 14-point deficit to a two-point lead. (It didn’t last.) And in 1988, Bush bounced from a seven-point deficit to a four-point lead. (It lasted.)

The 1996 bounces produced less drama because the lead never changed hands. There was movement: Bob Dole advanced from a 19-point deficit before his GOP primary to a four-point deficit after it. But that faded to a nine-point Dole deficit within a week, and shrank to 14 points after the Democratic convention.

The bounce comes from all the good vibes that are supposed to emanate from a nominating convention, which helps explain why Hubert Humphrey got only a weak gain in 1968 (trailing by 16 points before the Chicago convention and by 12 points after it). And in 1972 George McGovern got zero bounce; in fact, he fell from a 16-point deficit before his convention to a 19-point deficit after it.