Texas Watchdog is rolling out another enterprise story on Tuesday looking at the Houston Airport System. This time we put the spotlight on how a top city airport executive may have been hired by a foreign government for the exec's access to Mayor Bill White... while the exec was still working for the city of Houston.

It got me thinking that we should explain why Texas Watchdog has spent so much time digging into the Houston Airport. (Check out our cornerstone airport story here, in which Texas Watchdog uncovered a spiderweb of companies, including many incorporated offshore, linked to the airport system.)

We initially started digging because we were curious. The airport system's long-time and highly regarded CEO abruptly resigned soon after a meeting with Mayor White. Neither White nor CEO Richard Vacar was particularly forthcoming about what led to the resignation. (Vacar called it a retirement, for example.) We asked for a bunch of public records and started digging away -- and you'll see tomorrow we aren't done digging.

But a solid enterprise story in last Sunday's Houston Chronicle by Bradley Olson got me thinking of another reason we continue to dig.

Olson's story zeroed in on the Harris County-Houston Sports Authority:

Harris County may be forced to pay $4 million or more to the Harris County-Houston Sports Authority due to a cascading series of challenges initiated when $117 million in stadium bonds soured at the peak of the financial crisis last year.

The payments indirectly could upend a promise to taxpayers that public money would not be spent on professional sports stadiums.

So government officials initially told the public there'd be no cost to the taxpayer. And now, guess what? There might be a cost to the taxpayer -- to the tune of millions of dollars.

Call me skeptical, but it's cases like this that have stuck in the back of my mind as Texas Watchdog has probed the overseas, offshore work of the Houston Airport System.

Over and over again, city officials and airport experts have told us that the city bears no liability for the hundreds of millions of dollars of debt taken on by an airport-connected nonprofit and its business partners. Over and over again, they have said the taxpayer could never be on the hook for those millions if something went wrong. Over and over again, they have said the city could not be sued if the overseas projects went south.

But if the taxpayers' experience with the stadium is any guide, how can we be sure the promising politicians are right this time?

Perhaps we won't know for years.

In the meantime, though, we'll continue to dig around.