Even the village idiot knew such testimony was inherently unreliable and could routinely lead to the imprisonment of innocent people. Consequently, the accomplice witness rule demanded a defendant not be convicted of an offense on the testimony of an accomplice unless corroborated by other evidence tending to connect the defendant with the crime. Moreover, corroboration was not sufficient if it merely showed the commission of the offense. In other words, even if a jury believed everything an accomplice witness testified about, the law prohibited a conviction unless there was other evidence connecting the accused to the crime.
In recent years, two new laws were enacted requiring corroboration of other types of prosecution witnesses. First was the jailhouse snitch rule and then the drug informant rule. Both rules were similar to the accomplice witness rule in that corroboration was required before a jury could convict someone based on the testimony of these witnesses. Again, the inherently unreliable nature of this testimony raised the specter of convicting innocent persons.
Interestingly, Texas case law has held one type of unreliable witness cannot be used to corroborate another. For example, a jailhouse snitch cannot be used to corroborate the testimony of an accomplice, and vice-versa. The same holds true for drug informant testimony.
The challenge for the criminal defense attorney is getting the jury to commit to corroboration. In other words, if a jury believed the accomplice was telling the truth, they'd be reluctant to acquit someone based on their perceived moral responsibility to convict the guilty. Sometimes a crime is so awful, or the jury so afraid, that they invent corroboration in order to convict. The good news is that appeal courts use the corroboration requirement when evaluating evidence sufficiency questions. Stated another way, if there truly is no corroboration, the defendant has an excellent chance on appeal for a reversal.