Next year's mayoral race will be one of the most critical contests in the District's 30-year experience with home rule. With Tony Williams's name off the ballot, D.C. voters will be electing the city's fifth mayor. An overflowing plateful of tough problems and a turbulent political environment will greet the next mayor. Residents seem to sense the importance of the election, too, if the turnout for the first citywide mayoral debate is any guide.

On Wednesday evening more than 700 people filled the University of the District of Columbia's main auditorium, including the balcony, to witness the debate among the five Democratic candidates. As moderator, I got a chance to see the candidates up close, along with panelists Mark Plotkin of WTOP Radio, Tom Sherwood of WRC-TV and Examiner columnist Jonetta Rose Barras, also of WAMU. The evening, at least for me, had a few surprises.

The primary election is more than 10 months away, but the candidates, in terms of stage presence, seemed to be in midseason form. Their opening statements were polished, they labored hard throughout the forum to stay on message, and for the most part they avoided the kind of personal attacks that have marred previous mayoral contests. But, hey, it's early.

And it's not too soon to offer a few observations about the candidates and the impressions they may have wittingly or unwittingly left behind. The saving grace at this point is that time is on their side.

* Adrian Fenty. Tom Sherwood nailed the youthful-appearing Fenty with a question that exposed what is widely perceived to be the Ward 4 D.C. Council member's weakest spot: a lack of familiarity with municipal financing and the nitty-gritty of governance. Asked to name the three Wall Street rating agencies that have upgraded the city's bonds from junk-bond status, an embarrassed Fenty could name only one. The fumble wasn't lost on the audience.

But his enthusiasm for constituent work and eagerness to deal with problems at the grass-roots level also seemed to resonate with people who like the idea of a mayor who is unafraid to leave the ivory tower. He brings the kind of energy, enthusiasm and concern for people that many in the city find absent in the incumbent. Fenty, however, clearly needs to heavy-up his performance with more substance, if only to convince voters that he is as capable at governing as he is at campaigning.

* Michael Brown. He would not have been on the stage if his last name had been Smith. Brown is where he is -- in style, speech and the ability to connect with an audience -- because he is the late Ron Brown's son. That's not a slam. Michael Brown inherited his father's political instincts and smarts, so he knows how the game is played in a city such as the District. He also has a good feel for what moves people. What's missing -- or at least what Brown has yet to reveal -- is any evidence that he has the knowledge and experience to deal with the problems that he can recite so well.

* Vincent Orange. "Why is that man from Ward 5 running for mayor?" is the question on the lips of just about everyone who is not a committed Orange supporter. It's been on mine for a long time, too. On Wednesday evening Orange answered for himself, and he didn't do a bad job. In fact, setting aside his tendency to come across at times like a jackleg preacher, Orange does have a record of service on which to run. It's not overwhelming, but it is credible enough to take to other parts of the city. Unfortunately for him, Orange can't seem to resist the cheap tricks that may elicit smiles on the corner but perhaps not many votes on Election Day.

* Linda Cropp. Her experience, both as a school board member and as a longtime D.C. Council member and now chairman, loomed large. No other candidate on the stage could match the depth of her knowledge of the city, the operations of government or the intricacies of the legislative process. Cropp's answers were to the point.

And yet there was something missing, something distressingly absent in a candidate this early in the campaign: Let's call it vitality. Cropp didn't seem to be up for the rigors of a nearly yearlong campaign. If she's not, it could prove politically fatal. Instead of coming across as a seasoned, forward-looking public official, Cropp could end up looking like a tired old politician. That would be a pity, too, because she has all the ingredients to be a formidable contender.

* Marie Johns. This was, for me, the surprise of the evening. Gone was the hesitant and reserved Johns I met several months ago when she was launching her "listening tour." Her detachment gave way Wednesday evening to engagement, sweeping away any thought but that she's in this contest to win. This is not to say that the former telecommunications executive scored many points with her knowledge of city programs or issues before the mayor and council. But she didn't have to do that. An energetic, extroverted and visionary Johns was on display this week. The months ahead will tell whether she has the rest of the stuff to make a good mayor.

So here we are at the dawn of the 2006 campaign and it's not even January. This was a lively debate in a university auditorium. But the campaign is going to be waged out there in the neighborhoods, where organization, volunteers, financing and a candidate's stamina count. Where will we -- and they -- be in three months? Stay tuned.