Editor's note: Jason Johnson is an HLN contributor and professor of political science at Hiram College in Ohio. He is the author of "Political Consultants and Campaigns: One Day to Sell." He is on Twitter.
(CNN) -- There is no middle-of-the-road opinion on Rachel Jeantel, the "friend, not-girlfriend" of Trayvon Martin who testified in the George Zimmerman trial Wednesday and Thursday.
Some people see a surly, unreliable witness who's been caught telling several whoppers over the past year. Others see your average working class teenage girl, trying her best to stay composed while retelling the story of the death of her close friend under the most grueling of circumstances.
Which one did you see? It probably has a lot to do with what demographic boxes you check to identify yourself.
Since Zimmerman was arrested, legal analysts have predicted that Martin's "girlfriend," who was talking to him on the phone when he encountered Zimmerman last February, would be a crucial witness for both sides.
For the prosecution, Jeantel establishes Martin as a scared teen who was trying to run away from a stranger (Zimmerman) on his way back home. For the defense, pointing out the various versions of events Jeantel gave in interviews with the press, Benjamin Crump and the police would be essential to poking holes in the prosecution story that started off strong on day one.
But that's just strategy. The real impact of Jeantel is how a jury -- made up mostly of white women and mothers whose only knowledge of Martin comes from his friends and family -- would view this young girl.
The moment Jeantel sat down on the witness stand and started talking, my Twitter account and the #Zimmerman timeline exploded with comments:
"Her story has been inconsistent. I don't think the state should have called her, she'll never survive cross. Just seems mean."
"She is a horrible witness. The repetitive nature of her testimony is uggg."
"I would be pissed if my daughter/son talked & behaved this way while testifying"
"Rachel Jeantel is being made fun of and slandered on Twitter because of her looks and the way she talks."
These were comments that exploded in the Twitterverse mere minutes into Jeantel's testimony. Why?
Part of it is because she is a dark-skinned, plus-sized girl from a low-income neighborhood who doesn't speak the King's English. With that profile, some viewers automatically see her as non-credible and uneducated, and every frustrated or irritable word coming out of her mouth reinforced the stereotypes of black teens that all too many Americans (of all colors) believe in.
This is key because most of Jeantel's criticism was expressed long before cross-examination, when the holes in her story were exposed. This doesn't mean that any juror or viewer who found Jeantel problematic is necessarily prejudiced or pro-Zimmerman. However, the swiftness with which she was viewed as a good or bad witness by some had more to do with how she looked than what she actually said.
On the other side, an almost equal number of people -- mostly parents, young people, minorities, and those who work with young people -- found Jeantel to be a normal girl in abnormal circumstances. A single friend of mine in her 30s watching the trial in Washington, D.C., said to me: "Imagine if you had to get on the witness stand and talk about how the boy you had a crush on was shot and killed right after you got off the phone with him. You'd be upset and nervous, too."
If you work with teenagers or are raising them, you might have found Jeantel more sympathetic than abrasive. If you don't watch much news, maybe you chuckled and identified with the high school senior when she assumed all criminal investigations looked like "The First 48" on A&E. What some people viewed as sketchy behavior, others saw as authenticity.
Ultimately, after a cross-examination that was sometimes tense, sometimes hostile, and definitely riveting, we are left to determine whether Jeantel swayed the case for the prosecution or for the defense. That depends less on what came out of her mouth than on how the jury saw her before she opened it.
If they saw a 19-year-old woman who was hostile, irritable, and a walking-talking racial stereotype, it probably hurt the prosecution and painted a poor picture of Martin. If they saw a senior in high school who was nervous, sincere, and obviously still in mourning, it likely hurt the defense's narrative.
More than any other witness so far, I think the public will be split on Jeantel. No one is going to be swayed from their first impression no matter what she does, and that's never a good thing, no matter what side of this case you're arguing.