Former Maryland Gov. Martin O'Malley. (John Hanna/AP)

Martin O’Malley (D) says he plans to announce his presidential campaign in Baltimore. Perhaps he’ll used a burned-out police car or a looted storefront as his backdrop. The former Maryland governor and Baltimore mayor tried to blame last week’s unrest on structural problems in our economy, outsourcing and a failure to invest in infrastructure. Nice try. The fact is, O’Malley and the Democrats own Baltimore and the disaster it has become. As one resident who met O’Malley at an inner-city food drive last week put it, “He’s walking into the aftermath of his legacy.”

It’s not his legacy alone. The last time Baltimore had a Republican mayor was 1967, nearly five decades ago. Indeed, the state of Maryland has had just two Republican governors since 1969 (and one took office just four months ago). Baltimore is a deep blue city in a deep blue state. The mayor is a Democrat. Every member of the city council is a Democrat. The school system is run by Democrats (and their teachers union overlords).

So when you see Baltimore on fire, Democrats built that.

Baltimore is the poster child for the left’s failed war on poverty. In 1964, President Lyndon Johnson launched the Great Society. He promised, “Our American answer to poverty is not to make the poor more secure in their poverty but to reach down and to help them lift themselves out of the ruts of poverty and move with the large majority along the high road of hope and prosperity.”

Do you see a Great Society in Sandtown? I sure don’t.

Today, the national poverty rate is 14.5 percent, which is virtually unchanged from 1966, when most of Johnson’s Great Society programs first took effect. In Baltimore, the poverty rate is even worse, with 24 percent of all residents and 35 percent of children living below the poverty line. The unemployment rate for black men in Baltimore between the ages of 20-24 is 37 percent. To put that in perspective, the unemployment rate during the Great Depression was just 22.9 percent. You know you have failed when reaching the employment levels of the Great Depression would be progress.

The New York Times reported Monday morning on a new study which found that “among the nation’s 100 largest counties, the one where children face the worst odds of escaping poverty is the city of Baltimore.” Low-income boys who grow up in Baltimore earn 25 percent less as adults than low-income boys who moved away as small children.

In the Baltimore community of Sandtown-Winchester, where the riots took place, The Post reported on Saturday that city officials “injected $130 million into the community in a failed effort to transform it. Instead there are block after block of boarded-up houses and too many people with little hope.” Nearly half of all Sandtown-Winchester high school students missed at least 20 days of school in 2011 and just 6 percent graduated from college — less than a quarter of the rate for the rest of the city. The community’s murder rate is double the average for Baltimore (which, in turn, had the fifth-highest murder rate last year among major U.S. cities). The state spends $17 million a year just to incarcerate Sandtown-Winchester residents.

The problem, as former Baltimore Housing commissioner Daniel Henson III told The Post, was that the city knew how to build houses, but “what we did not know as well was how to improve human capital.” Clearly, the Democratic approach of throwing money at the problem has not worked. In 2014, Baltimore public schools ranked third in the country in per-pupil spending, behind only New York and Boston. Yet, according to the 2013 National Assessment of Educational Progress (NAEP), 55 percent of Baltimore fourth graders scored “below basic” in reading while just 14 percent scored at the proficient or advanced level. Meanwhile 54 percent of eighth graders scored “below basic” in math, while just 13 percent were proficient or advanced.

O’Malley says recent events in Baltimore should serve as “a wake-up call for the entire country.” He’s right about that. After five decades of virtually uninterrupted Democratic rule, Baltimore is an utter disaster. The left’s approach to poverty has failed.

Reflecting on Baltimore’s dismal record, a former aide to former Mayor Kurt Schmoke told The Post “We meant well.” I’m sure they did. But meaning well is no excuse for almost 50 years of failure.

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