Since people tend to be skeptical of raw accusations in TV commercials, the Dems have perfected this process with their willing accomplices in the press.
1) Early in the campaign opposition research uncovers a scurrilous tidbit that needs some "validating"
2) Go looking for a left-leaning, lazy reporter (99% of them these days)
3) Take the press moocher out for an expensive meal and then give them the file with orders of strict anonymity.
4)Wait for the story to run, confident that long stretches of the imagination will be given factual credibility.
5) In the final weeks of the campaign create commercials that declare "ACCORDING TO THE SAN JOSE MERCURY NEWS THIS GUY WAS ONCE MARRIED TO A BARNYARD ANIMAL"
This was done on 6 or 7 occasions to Bill Simon. It was really sickening. These lazy 28-year-old airhead reporters, too dumb to understand the difference between a shotgun and a hunting rifle are supposed to have gone to remote archives in New York City and the Bahamas and uncovered arcane records from 10 years ago. It just doesn't happen that way.
This stuff is assembled by seasoned gumshoes who spend hours in dusty basement poring over ancient documents. Sometimes its the opposition, sometimes its Planned Parenthood, or a major labor union that comes up with this crap. The cycle is as predicatable as the phases of the moon.