Watching presidential candidates promise to "fix" America fills me with dread.

A reason I have this reaction is that I've been doing reports for "20/20" on previous politicians' campaigns to "fix" child sex abuse.

Sexual abuse was always a problem, but in the early 1990s, something changed. Several pretty white girls were victimized at a time when the 24-hour cable-news cycle was hungry for new drama. Heinous child molestation became the big story. So publicity-seeking politicians clamored for new laws.

One result of their campaign was Megan's Law, which requires police to notify neighbors when a sex offender lives nearby. States were also ordered to establish registries so that when sex offenders are released from prison or put on probation, everyone can keep track of them.

It does seem important to know when a dangerous person lives nearby, but these laws have freedom-killing effects that go well beyond their proponents' good intentions.

For last week's "20/20", I interviewed sex offender Frank Rodriquez. Because he admits he repeatedly had sex with a child, he will forever be listed on the Texas sex-offender registry. His name and picture are posted next to those of murderers of children and a man who molested 200 kids.

But Frank's "crime" was different. He had sex with his high-school girlfriend. She says it was her idea.

Nikki was a 15-year-old freshman when Frank was a senior. Nikki's mom knew that Nikki and Frank were intimate and even took her to Planned Parenthood for birth-control pills. But her mother didn't like the relationship, and one night, she and Nikki got into a fight. Her mom went to the police and filed charges against Frank because the age of consent in Texas is 17.

The next morning, she decided to drop the charges, but the police said it was too late. They charged Frank with sexual assault of a child.

Frank's court-appointed defense attorney told him he had two bad choices: plead guilty and accept seven years' probation or go to trial and possibly spend 20 years in prison.

So he took the plea bargain. It kept him out of prison, but it gave him a different kind of life sentence: life as a registered sex offender.

Frank had to move out of his family home because his 12-year-old sister lived there. He lived by himself in a trailer. He needed permission from a judge just to go to his brother's high school football games.

And above all he was told, "Stay away from your girlfriend." Continued...