The Times reports that the Obama campaign has “unleashed an advertising campaign of a scale and complexity unrivaled in the television era.”

The huge gap has been made possible by Mr. Obama’s decision to opt out of the federal campaign finance system, which gives presidential nominees $84 million in public money and prohibits them from spending any amount above that from their party convention to Election Day. Mr. McCain is participating in the system. Mr. Obama, who at one point promised to participate in it as well, is expected to announce in the next few days that he raised more than $100 million in September, a figure that would shatter fund-raising records.