Maryland state troopers stand guard as residents clean up, Tuesday, April 28, 2015, after an evening of riots following the funeral of Freddie Gray on Monday, in Baltimore. (AP Photo/Evan Vucci)

This week’s riots in Baltimore raise many troubling questions but one that you are not likely to hear asked out loud in the national media is this one:

When will Democrats be held accountable for their failures in our major cities?

Take a look at the cities with the most profound problems – crime, high unemployment, crumbling infrastructure, racial tension, corruption, scandal – and you’ll find a common thread. Those cities have been run by Democrats for decades.

The last Republican mayor of Chicago left office in 1931. In Detroit it was 1962. Philadelphia 1952. St. Louis saw its last Republican mayor in 1949. In Baltimore, it was 1967.

Baltimore city government is a one-party monopoly. Every member of the city council is a Democrat. It’s also a one-race oligopoly. The mayor, the chief of police and the majority of the members of the city council are all black. More than half of Baltimore’s police officers are black. There is scarcely a trace of Republican or Caucasian DNA on any aspect of government in Baltimore.

Thus the very idea that the hopelessness and frustration felt by Baltimore residents is the fault of Republican policies or systemic white racism is simply ridiculous. Nor are the difficulties faced by Baltimore the result of a lack of “investment” in schools, job training, urban renewal or any of the other favored nostrums of the Left.

“Investing” (read: transferring wealth via taxation) is always the way to fix it for liberals. The fact that 40 percent of Baltimore’s city budget consists of such “investment” – in the form of state and federal funds taken from taxpayers nearby and far away and given to Baltimore to augment its own tax receipts – and that yet Baltimore remains one of the poorest major cities in America, presents not the tiniest bit of irony to liberals.

Among the complaints voiced by activists and protestors in Baltimore is the lack of opportunity in the form of good jobs. But that should surprise no one. In 1960, Baltimore had a population of more than 939,000. Today, it stands at 621,000 and falling. Employers have fled Baltimore to escape a hostile business climate and high taxes. Residents with the means to do so have fled high crime and diminished job prospects. What’s left is a population that is disproportionately unemployed, addicted to drugs and dependent on government.

All of this has happened while the Democrats have run the show in Baltimore – just as they have in America’s other failing cities – and just as they have for more than half a century. The results are now fully on display.

Given what Baltimore now suffers, it’s worth asking of those who keep voting in a Democratic monopoly:

If you’ve done something for 50 years and it hasn’t worked, shouldn’t you at least consider trying something else?