During that time, the Obama campaign pummeled Mr. Romney with negative advertisements, helping to sow unflattering perceptions of him.
Polls showed the law about to pass, but in the final weeks a barrage of television advertisements helped to defeat it.
Those advertisements helped stimulate growth in pork sales to American consumers, from $22.5 billion in 1988 when the program began to $37.3 billion last year.
Ronald Searle, the British cartoonist and caricaturist whose outlandishly witty illustrations for books, magazine covers, newspaper editorial pages and advertisements helped define postwar graphic humor, died on Friday in Draguignan, in southeastern France, where he lived.
That spot was co-sponsored by the Republican National Committee, which is allowed to split the costs with Mr. McCain on an unlimited number of advertisements, helping him to double the number of advertisements he can buy.
"Mike Dukakis showed that if you don't hit back at the very next moment that it can be effective," Dr. Dean said, recalling the 1988 presidential election in which Mr. Dukakis's refusal to respond to negative advertisements helped sink him.
In many cases, the Republican-oriented groups got involved in the races early on, battering Democratic candidates with negative advertisements, helping to set the tone in those districts, even if Democratic candidates and their allies were eventually able to outspend them.
