CHICAGO — The Illinois Supreme Court on Tuesday let stand a prison sentence of less than seven years for a white Chicago police officer convicted of killing black teenager Laquan McDonald that many criticized as far too lenient.

The high court offered no explanation for its 4-2 decision that denied a rare bid by Illinois' attorney general and a special prosecutor to get the justices to toss a lower court's sentence. One judge issued a strong dissent and one partially dissented.

The 40-year-old Jason Van Dyke, the first Chicago police officer sentenced for an on-duty shooting in a half century, could go free in as little as three years with credit for good behavior behind bars.

McDonald was carrying a small knife in 2014 when Van Dyke exited his squad car and almost immediately opened fire. Police video released in 2015 showed Van Dyke firing 16 bullets into McDonald, many after the 17-year-old had crumpled to the ground.

Speaking to reporters Tuesday, Illinois Attorney General Kwame Raoul stopped short of criticizing the court, though he went out of his way several times to note the four justices in the majority didn't offer a word of explanation for why they ruled as they did.

An appeal to the U.S. Supreme Court doesn't appear to be an option, including because the core legal issues have to do exclusively with Illinois law. Raoul acknowledged that his office had run out of options.

Asked whether Van Dyke's comparatively light sentence was an illustration of racial disparities in sentencing, Raoul paused before saying: "Suffice to say that I believe the sentence was inconsistent with the law."

Van Dyke's lawyer, Dan Herbert, heralded the ruling, saying he hoped it "will strike a fatal blow to the political exploitation" of McDonald's death. Raoul has previously denied that politics ever entered into the decision to push for a new sentencing hearing.

Jurors in October convicted Van Dyke of one count of second-degree murder, which carries a maximum 20-year prison term, and 16 counts of aggravated battery, which carries up to 30 years on each count. Leading up to sentencing in January, prosecutors asked for a prison sentence of at least 18 years.

Van Dyke went to trial charged with first-degree murder, which has a mandatory minimum prison term of 45 years. Jurors replaced it with second-degree murder after finding Van Dyke shot out of fear for his life, though that fear was unreasonable.

The February request for a sentencing do-over didn't say explicitly what many Chicago residents have said — that Van Dyke's punishment didn't match the severity of his crime. It focused instead on legal arguments around precedent and sentencing calculations.

Illinois judges can sentence people only for the most serious crime when they are convicted of multiple crimes for what amounts to a single act. A 2004 landmark ruling by the state Supreme Court said unambiguously that the crime with the higher penalty is the most serious.

But Cook County Judge Vincent Gaughan in January deemed the second-degree murder conviction the most serious, even though battery carries a longer potential sentence.

Justice P. Scott Neville Jr. noted in his dissent that Gaughan pointed solely to the dissenting opinion in the court's 2004 ruling when he sentenced Van Dyke.

"A dissenting opinion is not the law of Illinois," Neville wrote. "Indeed, it is the opposite."

Justice Thomas L. Kilbride, who partially dissented from the majority Tuesday, agreed with Neville on that issue.

In his seven-page explanation, Neville added that allowing a sentence that's not grounded in proper law undermines the public's sense of justice.