By Jim Ellis
Aug. 3, 2016 — The national post-convention polls are quickly being reported into the public domain and, as time has progressed from the weekend into the beginning of this new week, Hillary Clinton’s advantage increases.
It’s not particularly surprising that the former Secretary of State’s post-conclave bounce would neutralize the gains that Donald Trump made the previous week when he officially accepted his nomination. In fact, the principle reason the Democrats scheduled their convention in the immediate week after the GOP national meeting was to blunt any sustained momentum the Republican nominee might develop.
In a poll taken throughout the Democratic convention week, Ipsos Reuters (July 25-29; 1,433 likely US voters) found Clinton leading Trump 40-35 percent. When Libertarian nominee Gary Johnson is added, Clinton and Trump tie at 37 percent, while the newcomer had five percent.
After the convention concluded, however, Clinton began to pull away. Public Policy Polling (July 29-20; 1,276 likely US voters) gave the former US senator and First Lady a 46-41-6 percent edge over Trump and Johnson. The CNN/ORC study (July 29-31; 894 registered voters) sees an eight-point spread between the two candidates, 45-37 percent, with Johnson taking five percent. In a straight head-to-head ballot test between Clinton and Trump, CNN sees the Democrat’s margin growing to 52-43 percent.
The CBS News survey, taken during the exact same July 29-31 period (1,131 likely US voters) as the CNN/ORC poll, projects a slightly closer contest. Here, Clinton holds a similar five point lead 43-38 percent, with Johnson doubling to 10 percent preference. With just the two major party candidates tabulated, the spread is 47-41 percent.
The CBS poll is interesting because their analysts consulted history to compare Clinton’s four-point bounce with all other Democratic presidential candidates dating back to Hubert Humphrey in 1968.
Hillary Clinton is on the low end of the scale defined, ironically, by her husband Bill Clinton’s 13-point post-convention surge in 1992. The only other Democratic nominees to receive a double-digit boost were Jimmy Carter in 1980 and Al Gore 20 years later. The lowest were George McGovern in 1972 and John Kerry in 2004 who received zero increase after their convention proceedings. Humphrey in 1968 and Walter Mondale in 1984 received a two-point bounce.
In all instances, the candidates increasing their poll standing two points or less lost the general election, yet two of the three receiving the biggest bounces, Carter (’80) and Gore (’00) also lost, though the latter did win the national popular vote. The contenders getting the smallest bounces who won were Barack Obama in 2008 (three points) and 2012 (five points), and Bill Clinton in 1996 (four points).
Though the convention bounces certainly give the candidates and campaign participants a morale boost, the historical data strongly suggests little direct correlation between the candidates’ immediate post-convention standing and the final outcome in the succeeding November.