republican candidates far behind the front-runner, who hasn't spent a dime on television advertising. >> super pacs are a disaster. they're a scam. they cause dishonesty and you better get rid of them, because they are causing a lot of bad decisions to be made by some very good people. and i'm not blaming these folks, but i guess i could. >> reporter: some experts say big check writers are driven by a mix of business and ego. >> they're giving to people they think will support what they want. and they're giving to people that they know will answer their phone calls if they win. and they know will give them access and listen very carefully to what they want on a public agenda. >> reporter: so those gop presidential political ads you see on tv, more than 80% of them so far have been paid for by super pacs, that's according to a recent report from a nonpartisan watchdog group. but how successful those ads are still is an open question, with many candidates supported by super pacs doing poorly in the polls. for example. the report says jeb bush and the