D.C. LAWMAKERS spend a fair amount of time at the Wilson Building decrying developers and devising ways to make it harder to do business in the city. So it might actually have been constructive for so many members of the D.C. Council to attend the annual conference of real estate developers and major retailers. Hopefully they learned something about the needs and realities of doing business — lessons that won’t stay in Las Vegas.

Nine of the 13 council members, a record number, attended the International Council of Shopping Centers’ conference this past weekend, along with Mayor Muriel E. Bowser (D) and administrative staff. The contingent of 24 people was, The Post’s Aaron C. Davis reported, the largest of any city, prompting criticism about the use of city funds. No question there is value to the District in having a presence at this gathering. Other jurisdictions, including Maryland, also were represented. But it’s debatable (and that is being charitable) whether a supermajority of the council needed to make the trip. That the council was not immediately forthcoming with an estimate of costs suggests a certain defensiveness; it subsequently put the council’s cost at $30,000, while the cost for the mayor’s group was $13,000.

Whether the city’s money was put to good use remains to be seen. A major pitch was to grocers, especially to serve neighborhoods east of the Anacostia River. We hope the message fell on receptive ears, but a good sales pitch can go only so far. More critical is the kind of climate that exists for business, and here the District has been its own enemy, with lawmakers regularly coming up with new demands on companies in the ways they hire, compensate and operate. A recent prime example was the adoption of an extravagant family-leave program financed with a new tax on businesses.

The District today holds far more appeal for businesses than it did in past years of terrible crime and fiscal mismanagement. “Now,” said D.C. Council member Jack Evans (D-Ward 2), “everybody wants to come open a store in the District.” But council members who take that for granted run the risk of killing the golden goose, no matter how much wining and dining they did in Las Vegas.

By the way, here’s who made the trip: Mr. Evans; Brandon T. Todd (D-Ward 4); Kenyan R. McDuffie (D-Ward 5); Vincent C. Gray (D-Ward 7); Trayon White Sr. (D-Ward 8); Robert C. White Jr. (D-At Large); Anita Bonds (D-At Large); David Grosso (I-At Large) and Chairman Phil Mendelson (D).