The Baltimore riots and Freddie Gray's death may finally make criminal justice an issue in the 2016 campaign

Call it the Baltimore effect.

For the first time in more than two decades, America's broken criminal justice system looks to be a major issue in a US presidential campaign.

Ever since 1988, when George H.W. Bush used the infamous Willie Horton commercial to portray Michael Dukakis as soft on crime, crime issues have largely disappeared from campaign rhetoric.

In 2012, not a single question about criminal justice was asked in 24 presidential, vice presidential, and primary debates, Stephen Handelman notes in The Crime Report.

But in the wake of Baltimore's unrest sparked by yet another death of a black man, Freddie Gray, allegedly at the hands of the police - and after a year in which other victims such as Michael Brown, Eric Garner, Tamir Rice, and Walter Scott have become household names - suddenly criminal justice is on the front burner.

Linked to police brutality, overpopulated prisons, and sentencing reform, the issue is fraught with racial dynamics and presents challenges to even the most savvy politician.

On the Democratic side, Hillary Clinton was praised Wednesday for a forceful speech - the first substantive policy speech of her campaign - in which she called for an overhaul of the criminal justice system. She slammed "mass incarceration" and overly punitive criminal statutes that result in racial discrimination.

Her comments were powerful enough to outshine the instant cries of hypocrisy from critics who pointed out that she has long expressed support for tough-on-crime tactics initiated under her husband's administration. And during the 2008 campaign, she questioned rival candidate Barack Obama's proposal to abolish mandatory minimum sentences for federal crimes.

In her speech and other comments, she was also able to outflank former Maryland governor Martin O'Malley, her strongest progressive rival who was threatening to poach the liberal wing of the party.

O'Malley, the former mayor of Baltimore, found himself on the defensive most of the week, backpedaling from accusations that the mistrust of law enforcement and simmering rage in black neighborhoods stemmed from the crackdown on crime that he launched during his tenure from 1999 to 2007.

Rushing back from an overseas trip, O'Malley returned to Baltimore this week, expressed his condolences to Gray's family and emphasized that police shootings fell to their lowest point in decades while he was mayor.

On the Republican side, Baltimore presents even greater challenges to a party that has long pushed tough-on-crime policies. And it could upend the GOP's focus on slashing the budget for urban renewal programs.

Jeb Bush, the Republican hopeful who leads the polls, expressed sympathy for Gray's family but was very supportive of tough law enforcement policies, such as the "broken window" theory used in New York City by former mayor Rudy Giuliani during the 1990s.

Under that policy, minor crimes such as jaywalking and jumping subway turnstiles are punished in order to prevent those suspects from committing bigger crimes in the future. Bush also proposed conservative solutions to the anger in black communities - welfare and education reform.

Senator Rand Paul (R-Kentucky), the libertarian-leaning candidate, had hoped to attract some African-American votes by reaching out to such audiences and emphasizing sentencing reform in his speeches.

But he blew it. He "tried to present himself as a different kind of Republican. Then the riots happened," Eli Stokols wrote in Politico.

When he appeared on conservative radio host Laura Ingraham's show, Paul made headlines by quipping that his train came through Baltimore the previous night. "I'm glad the train didn't stop," he said.

Senator Ted Cruz (R-Texas) expressed sympathy for African-Americans frustrated about inequities in the criminal justice system.

But when asked about policy reforms, he avoided specifics, condemned the demonization of the police and blamed Obama for turning "us against each other" and stoking racial tension.

Senator Marco Rubio (R-Florida) was one of the few candidates who was absent on Baltimore, apparently not making any public comment about the unrest. In the past, he has tried to have it both ways, articulating support for criminal justice reform as a way to cut back regulation, a red-meat issue for conservatives. And he criticized proposals to reduce penalties for drug use and to legalize drugs, saying that would be a "great mistake."