John Nichols at The Nation reviews O'Malley's brand of moral politics and the actions that followed from it. Here are a couple of examples.
Like Jimmy Carter, Bill Clinton, and Barack Obama, O'Malley recognizes that Democrats must claim some moral high ground—rather than simply positioning themselves as savvy technocrats—to prevail in presidential politics. More importantly, O'Malley recognizes that claiming that moral high ground involves taking risks and doing the right thing even when it is not necessarily popular.
On marital rights
[A Roman Catholic,] he is pro-choice and he has been a leading advocate of marriage equality; when Baltimore Archbishop Edwin O'Brien urged the governor to oppose marriage equality, O'Malley replied, "I do not presume, nor would I ever presume as governor, to question or infringe upon your freedom to define, to preach about, and to administer the sacraments of the Roman Catholic Church. But on the public issue of granting equal civil marital rights to same-sex couples, you and I disagree." O'Malley signed the law and then defended it when opponents sought unsuccessfully to overturn the measure with a statewide referendum.
... O'Malley created a national stir last summer by speaking about immigration policy in smart, reasonable, and moral terms that put him at odds not merely with many other presidential contenders but with the Obama administration.
O'Malley's approach was not a radical one. But his emphasis on fairness and human dignity, as opposed to predictable political positioning, was refreshing. O'Malley did not deny the serious practical and political challenges that had arisen as thousands of children from Central America crossed into the United States in the spring and summer of 2014. He recognized that there were a lot of issues to be resolved with regard to the particular circumstances of the children—and with regard to broader need to reform the nation's ill-defined and frequently dysfunctional approach to immigration policy.
Yet, O'Malley never lost sight of the most important fact: The children who were entering the United States were children. They came, in many instances, as desperate refugees fleeing extreme violence, poverty, and dislocation in countries where the social fabric has been rapidly fraying because of destructive globalization schemes, corruption, and a horrific maldistribution of wealth.
... he placed the debate in a moral context that was rooted in American historical experience. In media interviews, the governor calmly explained, "I believe that it is contrary to everything that we stand for as a people to try to summarily send [refugees] back to death, whether it's in famine; death whether it's in the middle of the ocean; death whether it's in a war-torn area or death in a place where gangs are the greatest threat to stability and the rule of law and democratic institutions in this hemisphere."
On his election prospects
O'Malley sees what he thinks is an opening and he is making his move. More power to him. The race for the 2016 Democratic nomination needs contenders who are willing to push the limits in the debates and in the fight for the heart and soul of the party. Martin O'Malley brings some needed vision, and needed language, to the competition. He should be treated seriously, because of his own record and his own ideas, and because of his party's history of rejecting front-runners and embracing campaigns that speak a moral-duty language. O'Malley says, "We are still capable of acting like the compassionate, and generous, and caring people our grandparents expected us to become and that our children need for us to be." That is a morals message, a values message, and it has appeal—not just with Democrats but with a lot of Americans who might vote Democratic.