On Thursday, Mayor Nutter delivered his final budget address to City Council. More than once during his remarks, the mayor paused. Not a pause for effect. No. They were the kind of overly long pauses one resorts to when emotions rise dangerously close to the surface.

No tears were shed, yet the poignancy of the moment was not lost. Those in attendance were watching a good and - by his own admission - imperfect man, who through more than 30 years of public service has done his level best for a city he loves.

In 10 weeks, barring a November surprise from a Republican or Independent candidate, Philadelphia's Democratic primary voters will elect Mayor Nutter's successor. And, if history holds, they will select the candidate that best stands in contrast to the current one.

Consider that the black eye left on Philadelphia from the MOVE bombings of the Wilson Goode administration led, in 1991, to Philadelphia voters electing a Chief Executive Cheerleader, Edward G. Rendell, to restore the city's image.

The Rendell administration's focus on revitalizing Center City buoyed voters, in 1999, to promote Council President John Street - a self-proclaimed mayor for the neighborhoods.

And the corruption scandals of the Street administration awakened voter appetite for the good-government ethics reformer, Michael Nutter.

So, with the Nutter administration drawing to a close, what do the voters hunger for now? What would contrast with the current administration?

A congenial and influential relationship with Council, generally, and its president, in particular.

Mayor Rendell had Council President Street, who may have set a record for the number of unanimous Council votes he secured in favor of administration policies. And, Mayor Street had Council President Anna Verna. A few bumps, but mainly smooth sailing.

Mayor Nutter has had Council President Darrell Clarke. And it's been a "buckle your seatbelts" kind of ride. It's no secret that there is no love lost between Nutter and Clarke. Even when they seemed in agreement on an issue - such as increased funding for Philadelphia schools - teaming up to resolve it seemed an impossibility. What a shame.

Imagine what a positive collaborative relationship between the two might have yielded this city, especially considering the ways in which Philadelphia is thriving. We are less violent and a little less poor. We've invested more in our schools, our parks, and our libraries. And we are teeming with excitement over two upcoming world-stage events: the visit by Pope Francis in the fall and next year's Democratic National Convention.

So the inability of Nutter and Clarke to work together is indeed a shame. And while we can't change the past, we can learn from their mistakes.

On May 19, primary election day, voters should think about how the city would benefit if the executive and legislative branches of its government were rowing in the same direction. They should ask themselves which candidate possesses the leadership attributes necessary to forge a positive, collaborative relationship with Council.

The question does negate other attributes of a good mayor, such as technical skills and substantive knowledge. Those are important, but no one will know everything about topics as varied as recycling, animal control, pensions, and dredging. But that's why smart mayors surround themselves with knowledgable professionals, and why they prepare themselves to learn as they go. And there is help with this. For example, Harvard's Institute of Politics and the U.S. Conference of Mayors provide a tuition-free seminar on transition and leadership that offers new mayors a peer network, access to Harvard research, and a basic foundation in governing as taught by former and current big-city mayors.

That's one set of skills. The question about collaboration that voters must consider highlights an area often ignored in politics and governing. That is, do the candidates possess the "soft skills" of executive leadership? Can they attract allies and supporters to their vision? Can they influence dissenters? Can they work collaboratively? And, when all else fails, can they stomach getting on their knees - a la Rendell's blush-inducing characterization of his primary service as mayor?

How can voters evaluate candidates on such basic skills? Here are some things to consider.

Do they demonstrate a courage of conviction? Are they the kind to jump in front of a populist parade and pretend they are leading? Or can they say no, even when yes might be the more popular answer? Take it a step further: When they say no, can they offer a sound argument that gives us pause, that might stop our knee from jerking in protest?

Do they work collaboratively? This is not the same as trading votes and leveraging power. Rather, this is about a demonstrated track record of bringing together dissenters and supporters to attack a problem and effect a solution. This is not about exploiting might, but convincing others that one is right.

To help answer such questions this year, Philadelphia voters can avail themselves of a unique resource in Leadership 2015, a joint effort of the Committee of Seventy and WHYY/Newsworks. To learn more about the soft skills of leadership, the project team will interview some of the nation's most respected former mayors. What the team learns about leadership will serve as a foundation for questions to be asked in two upcoming debates, one a digital project that will engage both candidates and the public, and the second a candidates' forum on April 27.

In past elections, it seemed most important to consider what a candidate wished to achieve as mayor. The current struggles between administration and Council challenge us to consider a different question:

How will you forge working relationships to advance an agenda that benefits the people of Philadelphia?

Farah Jimenez is a member of the School Reform Commission, a community advocate, and a former member of the Republican State Committee.