Danny Cevallos is a CNN legal analyst and a personal injury and criminal defense attorney practicing in Pennsylvania and the U.S. Virgin Islands. Follow him on Twitter @CevallosLaw . The opinions expressed in this commentary are solely his.

(CNN) A California judge named Aaron Persky recently sentenced Brock Turner , formerly a Stanford athlete, to six months in jail for sexually assaulting an unconscious woman behind a dumpster, and then attempting to flee when discovered. This sentence has sparked national outrage and ignited a movement to recall that judge.

Before I go any further, let's get something out of the way: This is a light sentence. This is an unusual sentence. This is a sentence below the two-year statutory minimum. This is a sentence a different judge might not have handed down.

But this is still a legal sentence.

A recall? It's possible, but it's not an overnight process -- and we'll get to why in a minute. As for impeachment, it would set a dangerous precedent if jurists could be brought down by online petitions and Twitter campaigns, for a legal sentence.

To determine whether a case is "unusual," first, the court uses a list of factors to evaluate whether this is one of those rare cases warranting probation. It's true that one factor is whether the crime is "substantially less serious than the circumstances typically present in other cases." Those seeking to recall the judge have a strong argument that Turner's conduct is not "substantially less serious" than other crimes.

But that's only one factor. Others include:

-- [t]he defendant has no recent record of committing similar crimes or crimes of violence;

-- The defendant is youthful or aged, and has no significant record of prior criminal offenses.

One judge could have focused on the egregious nature of this crime. Another judge might focus on the lack of prior criminal behavior. Either is permissible, because no factor appears to be more significant than another. Reasonable minds -- and judges -- might certainly disagree.

Even if the judge concludes that the defendant is a candidate for a below-statutory sentence, he still has to apply additional criteria to decide whether to ultimately depart from the minimum sentence, and several of these are bad for this defendant, including:

-- Physical or emotional injury to the victim;

-- Vulnerability of the victim;

-- The defendant was an active participant;

But that same rule describes factors that this judge could have deemed favorable to this defendant:

-- The defendant was not armed;

-- The victim was not robbed;

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This is not me drumming up support for this defendant. What I'm describing is actually what the probation department concluded in its own rule-based analysis, preparing a presentence report for the court.

Interestingly enough, there might have been a slight misapplication of one of the factors by the court. At sentencing, one of the judge's more controversial statements justifying his lighter sentence was: "A prison sentence would have a severe impact on him." Yikes. That's not going to go over well.

It's hard to say, but His Honor might have been considering this factor: "The likely effect of imprisonment on the defendant and his or her dependents." The presentence report concluded the opposite: this criterion was unfavorable to the defendant because he has no dependents.

Can you see why? The "and" means the effect of imprisonment only matters if the defendant has dependents. In California, if you're looking for a probation-only sentence, it might help to have a wife and kids. Turner didn't have either; that factor should not have helped him.

Does that amount to a grievous error by the judge? It's hard to say, especially from a single quote. It could be a misapplication of a factor, or some extemporaneous musings from the bench. It's probably not tantamount to a misapplication of the law in its entirety. But who knows?

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There's no question that when judges depart from a statutory minimum, they are actively going outside their judicial comfort zone. Judges don't depart unless they think they have a really good reason, because the law requires them to show their work. Exhibit A to this principle is the suggestion that this crime "is substantially less serious than the circumstances typically present in other cases." A hotly disputed application of the rules to the facts, to say the least.

The rules make it clear: there is a presumption of incarceration in California, especially for such a deplorable crime. Persky's interpretation of these factors and conclusion that the defendant's previous record and character constituted "unusual circumstances" is neither beyond the law nor outside his discretion as the judge. But the ultimate sentence appears to be legal.

And that's why a movement to recall Persky, currently being led by Stanford law professor Michele Dauber, will likely be the only recourse for those looking to oust him. There are no apparent grounds for impeachment or allegations of judicial misconduct, based on this sentence alone.

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Judge Persky secured a new term this week (because he was unchallenged for the post, the election was canceled) and will serve another six years beginning in January, 2017. The #NeverPersky movement would have to wait 9 0 days after his new term of office begins, before beginning the recall process.

According to RecallAaronPersky.com , his detractors will need to collect a number of signatures equal to at least 20% of the votes cast in the upcoming November 2016 election in Santa Clara County to get a recall measure placed on the November 2017 ballot. They would then have to successfully campaign to get that measure passed.

They might succeed. In any state with elected judges, the constituency giveth, and the constituency taketh away. But it raises the question: is removing judges good for the spirit of the judiciary system, especially when the judge's sole transgression is a legal sentence? Judges should be able to impose sentences that may not be popular without fearing retribution.

Federal judges never worry about Change.org petitions, or "open letters" posted on Facebook, not because they are cold or unfeeling, but because their job is specifically designed to be immune to that kind of social pressure.

Similarly, in California, a judge can be disciplined for judicial misconduct, which can include removal from office.

The point here is this. In both the state and federal systems, judges are supposed to enjoy a modicum of independence, unless they are guilty of misconduct or other shenanigans. In states that elects judges, the voters can weigh in. If Judge Persky gets recalled, that's democracy in action.

But the overall message is concerning: If judges can be brought down for correctly applying the law, then ultimately, who ends up doing the judging?