The latest poll on casino gambling in Massachusetts brings troubling news for the casino industry, while it’s sure to lift the spirits of opponents hoping to keep casinos out of the Bay State.

A Suffolk University/Boston Herald poll, released Monday, found that 47 percent of voters oppose plans to bring casinos to the state, while 37 percent are supportive of the idea. The results mark a sharp contrast from a Suffolk/Herald poll from February, which found that 37 percent opposed casinos, while 51 percent backed them.

Other recent polling data suggest stronger support for casinos in the state, though hardly an overwhelming mandate. A recent MassINC Polling Group survey found that 49 percent of voters support casinos, while 39 percent oppose them.

While casino support in Massachusetts has fallen off considerably, the gambling industry rolled out its own survey numbers on Tuesday to try to counter any notion that casino support may be slipping nationally. The American Gaming Association, a Washington-based trade group representing casinos, commissioned a poll that claims US residents of all demographic groups and political views have a “favorable image” of casinos. The association reported that 87 percent of respondents believe gambling is an acceptable activity — even if they don’t gamble themselves.

The association says residents, by a 2-to-1 margin, have a generally favorable view of casinos. However, with 27 percent of poll respondents saying they had no opinion, the actual percentage with a positive view of casinos did not even clear 50 percent, with 48 percent reporting a positive view and 24 percent viewing casinos negatively.

In a conference call conference with reporters, the CEO of the American Gaming Association, Geoff Freeman, was asked about the apparent disparity between the AGA’s national polling results and those from the Suffolk/Herald survey of Massachusetts voters.

“You have a small band of critics who are continuing to spread antiquated notions about the industry,” he said. “And those antiquated notions, that concerted campaign they’re running, clearly has an effect on those survey results.” Freeman promised that the AGA would continue to “correct these falsehoods.”

Whether Massachusetts voters will have the opportunity to weigh in on the casino question remains to be seen. The Massachusetts Supreme Judicial Court is expected to rule by early July whether a question seeking repeal of the 2011 casino law can appear on the November ballot. Casino opponents gathered signatures to put the question before voters, but Attorney General Martha Coakley ruled that it could not appear on the ballot because it would effectively seize property rights of casino and slot parlor applicants without compensating them for the millions of dollars they have spent trying to get licenses. Casino opponents appealed Coakley’s ruling to the state’s highest court.

Even some Massachusetts casino supporters believe the decision should be left with voters. In the same MassINC Polling Group survey that found continued support for casinos, voters also said they supported putting the casino question on the ballot, with 52 percent in favor of the casino repeal appearing on the November ballot and 39 percent opposed.