This isn't fun, but it's very important to understand when bad news happens. Poll aggregators now show Obama losing roughly a third of his polling lead. The Rasmussen Tracking Poll out minutes ago shows a 43-43 tie. Let's understand what happened.
First, let's find out when it started and how much things moved.
| Biggest Lead | Date | Current Lead | Change |
538 | 5.7 | 6/29 | 4.4 | -23% |
Pollster | 6.1 | 6/26 | 3.7 | -39% |
RCP | 7.1 | 6/29 | 4.2 | -41% |
538 shows the lowest high and the highest low in terms of Obama's lead. That's likely because 538 factors in additional data such as historical demographic voting patterns, sample sizes of polls, and pollsters' track records. It's up to you whether to believe Obama has lost 1/4 of his lead, 2/5 of his lead, an average of 1/3 (34.3%) of his lead, or 100% of his lead (as in, the latest Rasmussen poll being ahead of the curve).
Also, 538 and RCP use the median date and Pollster uses the end date when listing the date a poll occurs, making it stranger that Pollster puts Obama's largest lead three days ahead of the other pollsters.
So what happened around this time? Was it one incident? Was it a narrative that took shape? Was it a combination of narratives, none of which particularly stands out? The first contributing incident likely occurred at least a couple days before the polls picked up movement. If anyone can find any research into the lag time between an event or meme and poll movement, please share.
Here's a timeline of campaign headlines beginning 6/19, a week before the apex:
TIMELINE
6/19: Obama opts out of public financing, McCain calls it a "big, big deal." Debate over offshore drilling continues from 6/16. Obama/Clinton unity event announced. Obama apologizes to Muslim women barred from stage. Obama starts 18-state ad campaign.
6/20: Obama says he prefers no telecom immunity, but would vote for new FISA legislation that includes immunity.
6/23: Charlie Black says terror attack could help McCain. McCain offers prize for better electric car battery.
6/24: McCain calls offshore drilling benefits "psychological," calls Obama "Dr. No" on energy. Bill Clinton offers one-sentence press release of support for Obama.
6/25: Obama defends FISA position to reporters, says death penalty should be option in child rape cases. McCain names his energy plan the Lexington Project.
6/26: Obama and Clinton hold first unity event. Obama says SCOTUS gun ruling provides "much-needed guidance." GOP frames Obama as saying no to energy proposals in web ad.
6/27: McCain still complaining about lack of town hall debates.
6/28: McCain, Obama address Latino officials.
6/29: Clark says riding in a fighter plane and getting shot down is not a qualification for president.
6/30: Obama rejects Clark's comment. Obama says he thought "General Betray Us" ad was too divisive.
7/1: McCain praises Roberts and Alito, says Obama justices would be too liberal. During trip, McCain pledges to free American hostages in Colombia.
7/2: American hostages freed in Columbia. McCain knew. Obama opposes CA marriage discrimination amendment. Black conservatives call Obama racist in radio ad.
7/3: Obama tells netroots he agrees to disagree on telecom immunity. Says 16-month Iraq withdrawal timeline was always predicated on troop safety, will "continue to refine" Iraq policy.
7/4: Jesse Helms dies.
7/5: Obama defends that his Iraq position has not changed.
7/6: New RNC ad praises McCain's energy proposals, claims Obama just says no.
7/7: Obama makes Invesco Field nomination speech official. McCain pledges to balance budget by 2013.
7/8: Obama rejects flip-flop meme. McCain jokes about killing Iranians by exporting cigarettes to them. McCain pledges comprehensive immigration reform, Obama hits McCain on immigration, both candidates were before Latino audiences. Both candidates have been making a lot of efforts to court Latino vote. Obama announces new ad on energy plans.
7/9: Obama votes to immunize telecom companies for diverting all telecom traffic to NSA. Tape of Jackson wanting to cut Obama's nuts off surfaces. Merkel chides Obama about "electioneering" abroad. Obama's kids make TV appearances.
7/10: Gramm calls America "a nation of whiners" over a "mental recession." Obama temporarily forgets to solicit Clinton dollars at event.
I have my hunch what caused the polls to move, but I'd rather get your take: