A rash of conference cancellations, and a presidential admonishment peppered with a Las Vegas reference last week, has unnerved politicians and resort executives who are fearful that the all-important convention industry could be on the verge of collapse.

“It’s certainly a moment we should all pay great attention to,” said Jan L. Jones, senior vice president for Harrah’s Entertainment, which had a 30 percent decline in convention business in January compared with a year ago at its seven resorts on the Strip. “Las Vegas has long tried to balance the image of party town, serious town. This is an opportunity for us to remind business why they do business here, and it’s because it’s the best value.”

In the last month, 30,000 hotel room nights booked for conferences have been canceled at an estimated loss of $20 million to the city, according to the Las Vegas Convention and Visitors Authority.

Some of those rooms were reserved for a Goldman Sachs technology conference, which was moved to San Francisco this month. And the figures do not include 17,000 people who were expected to attend a State Farm agents’ convention this October. That conference was canceled Wednesday.

Las Vegas had already seen a 4 percent drop in visitors in 2008 from the year before and a decline of 6 percent in the number of conventions and events held here in that same period. The number of visitors was down 11 percent in December from a year before.

Another conference cancellation came from the Automotive Market Research Council, which was supposed to meet at the Planet Hollywood resort in March.

“We thought it would be a harder sell for our members to get approval” to go to a Las Vegas event right now, said Darren Green, vice president of the group. Mr. Green said the event had been called off as a cost-cutting measure.

Anxiety over the matter escalated last week after President Obama told an audience in Elkhart, Ind., that companies “can’t go take a trip to Las Vegas or go down to the Super Bowl on the taxpayer’s dime.” The remark was taken by many here as an attack.

“The mayor heard the words ‘Las Vegas’ — he didn’t hear any other city — and people are telling me that they’re not coming to Las Vegas because the president doesn’t want them to,” said Mayor Oscar B. Goodman, who at first demanded a White House apology but later in the week said he just wanted a clarification.

“There’s an impression out there,” Mr. Goodman said, “that somehow if you come to Las Vegas, it’s going to reflect on your business culture, and that’s a bunch of hooey.”

The White House has not commented directly on the matter. But the Senate majority leader, Harry Reid, Democrat of Nevada, said on the Senate floor Wednesday that Rahm Emanuel, the White House chief of staff, had told him that “the president’s criticism was aimed at the potential use of taxpayer funds for junkets and in no way reflects his thoughts about any one particular city.”

Mr. Goodman and local meeting planners insist that they have heard from companies who said Mr. Obama’s remarks scared them away, but Ms. Jones, the Harrah’s executive, said no company had made that connection while talking to her.

The cancellation that has particularly rankled Las Vegas was the one by Goldman Sachs, which received $10 billion in bailout money. The company issued a statement saying the decision was “based on our best efforts to operate according to the requirements of the new landscape of our industry,” but a $600,000 cancellation fee charged by the hotel has led some to question that explanation.

“I think it was a public relations move,” Ms. Jones said. “Why would you pay a cancellation fee and go to a city that’s more expensive to get there and where the cost of food is more expensive because you don’t have as many options? There’s no way that that ended up less money, and if the issue is really a responsible use of taxpayer dollars, doesn’t that mean you look for the best value which is the lowest price?”

With Las Vegas on the defense, competing destinations sense an opportunity.

Mark Theis, executive vice president of the Chicago Convention and Tourism Bureau, said he planned to point out to meeting planners that “people aren’t going to raise their eyebrows” about a company holding an event in his city.

“Now more than ever, it’s going to be in our favor that glitz and what’s new this week in Vegas isn’t going to resonate to the show managers at a time when everyone’s being scrutinized,” Mr. Theis said. “When you take out the casinos and all the recycled chefs, what else do you really have there? Splash has a limited shelf life.”

Ms. Jones zinged back: “They can be licking their chops, but the minute we tell our story, they can’t compete. Ever. Counting Las Vegas down and out, given the entrepreneurial spirit at work here, is just foolish.”