It should not be particularly surprising to learn that a labor union, in this case Teamsters Local 17, wants to organize those Denver city workers who are not already represented by a collective bargaining agreement, and that the coming months are viewed as "our day in the sun," as Local 17 official Ed Bagwell puts it.

When Denver succeeded in landing the 2008 Democratic National Convention, it was inevitable that organized labor would recognize it as an opportunity to expand its ranks wherever possible (beginning with downtown hotels). And after Gov. Bill Ritter encouraged bargaining units of state workers by executive order, unions concluded that their efforts to increase membership would be accepted more readily elsewhere - and perhaps especially in Denver, given the current labor-friendly makeup of the Denver City Council.

What is surprising about the Teamsters' upcoming bid to organize the more than 7,000 city workers not covered by collective bargaining - the union will reportedly conduct a petition drive next week - is the insistence that it can be done solely with the approval of the City Council and therefore without a sign-off by voters.

The contention is surprising because it is false.

The City Charter seems clear that voters must approve collective bargaining for municipal workers, as occurred years ago for employees of the police, fire and sheriff's departments. Article 9 of the charter creates the Career Service system that governs the personnel system for nonunion workers. Its provisions can't be overridden or pre-empted by statute.

Bagwell's insistence that City Council can, by ordinance, circumvent the charter is at best an invitation to legal challenge. If city workers ultimately are to be represented by Teamsters Local 17 or any other union, Denver voters must be the ones to decide.

Should such a vote occur, we hope Denver residents sympathetic to what union leaders like to refer to as "working people" will keep in mind that union representation does not come without a cost to an employer. From the taxpayer's point of view, the most worrisome achievements of collective bargaining in the public sector may be restrictive work rules and the arbitration of grievances. Such bureaucratic rules and procedures erode efficiency and management prerogatives at a time when the public sector is under increasing pressure to mimic the flexible attention to customer service exhibited by the best private companies.

A fuller discussion of the wisdom of granting collective bargaining to city employees must await another day. In the meantime, council members - and of course Mayor John Hickenlooper - should leave no doubt where they stand on the question of whether voters have the final say.