The city of Houston can’t deny Southwest’s proposal to open Hobby Airport to international commercial flights based on economic arguments alone, City Attorney David Feldman informed the mayor informed the City Council late last week in a memo attached to a legal opinion.

Feldman wrote, “…consideration of such economic issues for the community cannot be controlling; the City’s obligation to provide reasonable accommodation to Southwest is paramount, irrespective of such issues.”

Here’s Feldman’s memo:

MemoToCouncilSWA

The legal opinion comes just in advance of a scheduled hearing on Tuesday at which Southwest and United Airlines, which opposes Hobby expansion, are expected to debate whether having two international airports makes economic sense for Houston.

The Southwest plan calls for the addition of a Customs facility and five gates to Hobby. Though a city-commissioned study concludes that Hobby expansion would be a boon for the Houston economy, a study by United warns that it will cost 3,700 jobs, nearly $300 million a year in economic activity, reduced routes from Bush Intercontinental and the transfer of some United operations to other airports.

But a 14-page memo from attorney Peter Kirsch of the firm Kaplan Kirsch & Rockwell, indicates that the economic debate could be moot in the face of obligations the city has to the Federal Aviation Administration as a condition for receiving millions of dollars a year in federal funding.

Kirsch wrote “… the City is legally obligated to accommodate the reasonable needs of Southwest.”

He also wrote:

In meeting its obligations to the federal government, the City is required to negotiate in good faith with Southwest to provide the space and/or facilities that Southwest has requested to meet its needs for international service.

Kirsch leaves the door slightly ajar for grappling over whether this means the Southwest plan is a legal slam-dunk. The city should be guided by the overarching principle that the city is required to provide access on reasonable terms and without discrimination, Kirsch wrote.

But, he added:

The interpretation of this principle is unusually complex in this instance because there is no controlling precedent either in case law or under regulations, policies or determinations issued by the Federal Aviation Administration (FAA) that are precisely applicable to the facts presented here.

A United spokeswoman sent an email message that the company disagrees with the legal opinion.

Here’s Kirsch’s memo:

Kirsch Memo

Southwest, of course, appears to agree with the legal analysis. A spokesman emailed a statement: