Inside an elegant art-filled room at Hoyt Sherman Place last week, a crowd of wealthy and influential leaders listened as the mayor of Denver talked up the need to spend more on culture.

On the sidewalk, a lone dissenter walked back and forth, sweating in the sun, with a “No Tax Hike” sign.

The mayor was John Hickenlooper, an unusual and hugely popular politician who makes a terrific case for promoting regional government and spending on culture. Supporters of the proposed sales tax increase brought him here to report on Denver’s success, and he delivered in an engaging style.

Unfortunately, he was preaching to the choir. If you could haul him around town and have him speak directly to everyone who’s planning to vote on this issue next month, you would soon have yourself a higher sales tax. But thousands of potential voters weren’t there, and most of them aren’t hearing any inspiring presentations.

Just the day before Hickenlooper’s talk, I heard important business leaders ask why no one seems to be trying to sell the sales tax to the electorate. It’s starting to look as if the insiders are hoping only their fellow insiders will show up to vote.

Or maybe the insiders have convinced themselves that they’re dealing in common sense, and common sense will prevail. That’s Hickenlooper’s philosophy. When he was elected, he announced to a gathering of civic leaders that the days of vicious competition between Denver and its suburbs were over. Just like that.

When a big company came to town fishing for a package of government incentives, Hickenlooper told the corporate representatives that he didn’t care whether their company located in Denver or in the suburbs.

And when it came to spending money on culture, no debate. Sure, professional sports are big in Denver, but Hickenlooper and his staff measured attendance and found that cultural attractions are even bigger.

In his view, raising the sales tax and lowering property taxes is an easy call.

Despite the pro-culture theme, only once did he sound like a patrician, disconnected from the world of the less fortunate. He was asked if increasing the sales tax is a regressive approach that will hurt lower-income families. He remarked that wealthy people buy nicer clothes and more expensive stuff, so they’re the ones who will carry the sales tax burden, not the little guy. After all, he said, you can buy a nice shirt for 15 bucks at Target.

That seems to miss the point. The little guy will be paying that extra sales tax for lots of things every day on a limited budget. Meanwhile, opponents of “Yes to Destiny” contend that the big shots will reap a windfall through the reduction of property taxes and won’t even notice the difference in the sales tax.

After the speech, George Davey of West Des Moines was still striding up and down the sidewalk. He looked awfully lonely out there, compared with the happy crowd eating and drinking inside. But he reported that his Web site, www.nolocaloption.com, is getting up to 1,000 hits per day.

Davey was far outmaneuvered in the battle of Hoyt Sherman. Next month, when more troops arrive, we’ll see how the war turns out.