Ezra Klein points to some charts made by Richard Johnston and Emily Thorson on candidate favorables during the 2008 election:
The first graph is simple enough: It's the poll standing of the two candidates. The dark vertical lines show moments when Sen. John McCain's numbers dropped precipitously.
Graph number two shows assessments of the economy. The voters were pessimistic and became more so as the campaign wore on. But the line doesn't correspond to McCain's falls.
The third graph shows the average favorability toward the presidential and vice-presidential candidates. Obama and Biden, you'll notice, seem virtually independent of each other. But McCain's drops are almost entirely predicted by Palin's much longer falls. It seems that every time Palin lost respect among voters, a certain portion of those voters turned against McCain, too.
As well they should have. In my view, McCain should have retired from public life after this debacle. It showed he was unfit for higher office, incapable of making sober decisions, incompetent in staffing, and incredibly reckless with this country's national security. Instead, the MSM refuses to follow up on the question he needs to be asked: what were you thinking? And when will you apologize to your supporters, allies and contributors?