– For decades, political activists in Portland have argued that the city would be better off with a popularly elected mayor.

It took three elections — one to create a charter commission, one to approve the charter changes and, finally, one to elect a mayor — to settle the question. On Monday, Portland residents got a chance to see what they have been arguing over, not as an abstract concept but in the person of Michael Brennan.

So after all that work, what did they get? Well, the packed room at the Ocean Gateway terminal Monday saw a political leader at the top of his game, speaking to a wide range of constituent groups, paying attention to each of the issues they consider important, but putting them in a larger context of a whole city moving forward.

What Brennan presented was not a string of promises or programs, but a unified vision for a city where housing, education and opportunity for all would feed economic growth. A city where development and preservation would succeed together, and one in which the current residents would leave future generations something to be proud of.

Each bullet point in the speech got rousing applause from the entire room, not just the people who came in support of that specific issue.

Maintaining that sense of unity is the biggest challenge Brennan will face leading a city in which power has been dispersed among members of the City Council, the appointed officials in City Hall and the neighborhood and business groups, who all have different ideas about what’s most important.

How his ideas will translate into policy will be seen soon, perhaps starting today, with his breakfast address to the Portland Regional Chamber and continuing tonight as he chairs his first City Council meeting. On the agenda is the contentious issue of the Occupy Maine encampment, which challenges the core beliefs of many Portland residents on all sides of the issue.

The abstract arguments are over. Portland has a real mayor and now time will tell whether that will make a difference as the city faces the challenges ahead. Brennan’s success will depend on his ability to maintain the unity he described in his speech — not just before a friendly crowd but in an environment where people have real differences that are not easily bridged. But one thing is for sure: In his first speech, Brennan set the right tone.