(CNN) Race has divided the Roberts court like nearly no other issue.

The justices have wrangled over how openly to talk about their differences. And now, as a new session begins, the court is delving into a set of racially charged cases in the explosive context of the criminal justice system.

The disputes evoke some of the hostile rhetoric of the presidential campaign and real conflicts seen on urban streets: Slurs against Mexican-Americans. Testimony that black defendants are more dangerous than whites. A claim that police used racial epithets during an arrest then fabricated evidence.

The cases could especially test a Supreme Court that has been trying to smooth over differences since the February death of Antonin Scalia and no Senate action on US Appeals Court Judge Merrick Garland, nominated by President Barack Obama to succeed him.

The cases also arise as individual justices have been speaking more pointedly about the state of race in America.

In an interview soon after the July 7 killings of five Dallas police officers during a protest of police shootings of black men in Louisiana and Minnesota, Justice Ruth Bader Ginsburg voiced distress.

"We never realized what was the promise of the '60s," she said, responding to a question about recent killings. "With all the equality legislation, the Fair Housing Act [of 1968], the Voting Rights Act [of 1965], Title VII [of the Civil Rights Act of 1964], we still live in a highly segregated society. Black communities and white communities. Black schools and white schools."

Justice Sonia Sotomayor, the first and only Hispanic justice, has increasingly referred to racial divisions.

"[I]t is no secret that people of color are disproportionate victims of this type of [police] scrutiny," she wrote as she dissented in a June police-stop case. "For generations, black and brown parents have given their children 'the talk' -- instructing them never to run down the street; always keep your hands where they can be seen ... all out of fear of how an officer with a gun will react to them."

The justices have been riven more broadly on race, in cases covering school integration plans, municipal hiring, voting rights and college affirmative action.

In June, when Justice Anthony Kennedy voted for the first time to approve a university admissions program favoring minorities, he voiced new concerns about racial isolation and stereotyping.

Chief Justice John Roberts dissented then and has been firmly on the other side of the issue. He has expressed skepticism for remedies intended to promote diversity or counter historic discrimination. In 2013, he won a narrow majority to limit the reach of the Voting Rights Act in the Shelby County, Alabama, dispute.

In earlier cases, he referred to "a sordid business, this divvying us up based on race" and insisted, "The way to stop race discrimination on the basis of race is to stop discriminating on the basis of race."

Sotomayor turned that view against him as they tangled in 2014, saying, "The way to stop discrimination on the basis of race is to speak openly and candidly on the subject of race."

Only Ginsburg joined her in that opinion, dissenting as the majority upheld a Michigan state referendum prohibiting racial preferences in government programs. Justice Clarence Thomas, the sole African-American on the court, has been on the other side of affirmative action, believing it violates the Constitution's equality guarantee and can be stigmatizing to minorities.

Emerging against the backdrop of the presidential campaign and national controversy over policing, the new cases could inflame such tensions at the court.

All involve legal questions that go beyond race and ethnicity. A dispute from Colorado, for example, pits a defendant's right to fair trial against a longstanding principle safeguarding private jury deliberations.

The case began in 2007 when Miguel Pena-Rodriguez was accused of sexually harassing and attempted assault on two teenage girls in the bathroom of a horse-racing track.

During deliberations, a juror known in the record as H.C. said: "I think he did it because he's Mexican and Mexican men take whatever they want." He also dismissed Pena-Rodriguez's alibi witness as "an illegal."

After Pena-Rodriguez was convicted of sexual harassment, two jurors told defense lawyers about H.C., and his lawyers tried to use their statements to challenge the fairness of the trial.

Denying the request for a hearing, the Colorado Supreme Court said H.C.'s comments, no matter how "ideologically loathsome," did not merit an exception to jury deliberation secrecy.

Two years ago, the Supreme Court foreshadowed this dispute when it reinforced the principle protecting deliberations but said in the opinion by Sotomayor that, "There may be cases of juror bias so extreme that, almost by definition, the jury trial right has been abridged." The new case will be heard October 11.

A long-running Texas appeal spotlights a psychologist's testimony during sentencing that Duane Buck, an African-American convicted of the 1995 murder of his former girlfriend and a male friend, was statistically more likely to commit future violent acts than a white defendant.

Buck contends he was denied effective assistance of counsel; his lawyers had hired the psychologist to testify on his behalf. Lower courts ruled that Buck lacked the "extraordinary circumstances" needed to reopen his case.

Five years ago when the high court rejected a separate appeal from Buck, two justices (Sotomayor and Elena Kagan) said his case was "marred by racial overtones" and should be reviewed.

Three others justices (Samuel Alito, Stephen Breyer and Scalia) deemed the psychologist's testimony "bizarre and objectionable" but were among those rejecting Buck's petition. His new appeal will be heard Wednesday.

When can citizens sue for 'malicious prosecution?'

The third racially charged dispute also up Wednesday explores when a person may sue for "malicious prosecution" based on Fourth Amendment protection against unreasonable searches and seizures.

The dispute traces to March 18, 2011, when Joliet, Illinois, police officers stopped a car for failure to signal a turn and pulled Elijah Manuel from it. Manuel's lawyers told the justices in a filing that an officer him pushed him to the ground and said, "You remember me, street punk? Now I got you... ." The officer used a racial slur on Manuel, who is African-American.

Police found a bottle of pills that Manuel said were vitamins but that officers contended were illegal Ecstasy pills. Manuel said tests at the scene and in a police lab showed the pills did not contain controlled substances. Police claimed the opposite, leading to his indictment for unlawful possession. When Manuel's lawyer asked for a copy of lab results and it was clear the pills were not illegal, Manuel was released from jail on May 5, 2011.

Manuel sued for "malicious prosecution" on April 22, 2013, possibly beyond a two-year statute of limitations. The case involves several procedural issues, but an overriding question is whether Fourth Amendment protection extends beyond an arrest, through arraignment, and can serve as the basis of a "malicious prosecution" claim.

The Innocence Network, a decade-old consortium of 69 groups representing prisoners, emphasized in a "friend of the court" brief the possible consequences of Manuel's case for minorities: "Those incarcerated as a result of police misconduct ... suffer extensive harm. Racial minorities, the poor, and the uneducated disproportionately suffer these effects."