Why It's Usually A Huge Mistake For People To Testify In Their Own Defense

Reuters/Joe Burbank/PoolGeorge Zimmerman is greeted by defense counsel Don West at the start of his trial in Seminole circuit court in Sanford, Florida, July 8, 2013.George Zimmerman's lawyers rested their case Wednesday without calling him to the stand, and it was probably a wise call. His testimony could have been a disaster.

The risks of having defendants screw up during testimony or brutal cross-examination far outweigh the benefits, experts say.

Lawyers "try to control every aspect of their case as much as possible so as not to leave anything to chance," jury consultant Dr. Marshall Hennington told us. "If George Zimmerman were to testify and not come across to the jurors as being very believable, the defense's entire case would crumble and that would negate every shred of expert testimony that the jurors heard throughout the trial."

It's one thing for prosecutors to point out inconsistencies in a defendant's story. It's far more damning if a jury can watch a prosecutor illustrate that a defendant is a liar.

As another trial expert, Dr. Amy Singer, told us, "Once they contradict themselves: game over."

To be sure, jurors might be skeptical of defendants who refuse to testify. "If they don't have anything to hide, then why won't they take the stand?" jurors might ask themselves.

It's still probably not worth the risk of putting defendants on the stand — especially since prosecutors have the "enormous burden" of proving guilt beyond a reasonable doubt, defense lawyer Barry Slotnick told us. Slotnick represented notorious "subway vigilante" Bernhard Goetz, who also didn't testify in his own defense.

"Good defense lawyers are never troubled by the fact that they can't put their client on the stand. Most of my cases I've won my clients did not take the stand," Slotnick told us.

Of course, some clients do take the stand. "Mormon Casey Anthony" Jodi Arias spent 18 grueling days on the stand, during which she was forced to explain countless lies and answer many questions about her sex life. But her lawyers probably knew she already didn't have an good case.

The Zimmerman case is a lot more complicated. There's varying eye witness testimony as to which guy was on top of the fight, and nobody knows whether Zimmerman or Martin was screaming for help on a 911 call.

There are also some holes in Zimmerman's own story, but fortunately for his defense, he won't have to explain them to jurors himself.