WASHINGTON — Legislators and regulators who started the headlong enlargement of legalized playing within the United States are actually transferring in spots nationwide to tighten oversight of the playing business, significantly because it pertains to promoting which will attain underage bettors.

The crackdown extends to bettors themselves, as not less than three states have responded to a soar in abusive conduct by moving to bar gamblers in the event that they threaten or harass athletes after misplaced bets.

This extra aggressive strategy towards on-line betting is obvious in nations world wide, together with Australia, Belgium, Canada, the Netherlands and the United Kingdom, the place officers in current months have enacted or proposed new on-line betting restrictions, in some circumstances banning celeb sponsorships and practically all promoting.

Nationally, 33 states and the District of Columbia provide authorized sports activities betting, with Kentucky, Maine, Nebraska and Florida up subsequent. That means greater than half of Americans dwell in locations the place sports activities betting is permitted, 5 years after the Supreme Court overturned a regulation that had prohibited most states from legalizing the follow. Collectively, Americans have legally wager over $220 billion on sports activities for the reason that court action in 2018.

In the United States, the tweaking of state laws and legal guidelines began this winter in states together with New York, the place cellular sports activities betting generated $16.5 billion in bets and a rare $909 million in new tax and licensing income within the first yr it was authorized.

But the explosive progress of legally sanctioned, on-line betting on sports activities additionally produced rising considerations that it might trigger hurt. New York responded by proposing new rules that prohibit any promoting on school campuses or is “aimed at persons under the minimum age,” which in New York is 21, whereas Ohio stepped up enforcement actions.

“Folks are waking up to the need to intervene and not wait a decade and have the full brunt of harmful effects of this, particularly on minors,” mentioned Matt Schuler, government director of the Ohio Casino Control Commission, who mentioned he was extraordinarily disenchanted with content material of promoting in his state as betting began this yr. “The industry will certainly never police itself.”

An estimated $1.8 billion was spent promoting on-line playing final yr in native markets within the United States, in keeping with BIA Advisory Services, an business information aggregator, up practically 70 % in only one yr, contributing to a way amongst sure state regulators — and plenty of sports activities viewers — that the airwaves had change into too saturated with sports activities betting advertisements.

Over the final six months, Maryland, Maine, Massachusetts, Ohio and Connecticut have enacted or proposed new guidelines regarding sports activities betting, a few of which are actually in impact or awaiting last approval. The measures differ by state, however most intention to forestall misleading advertising and marketing or promotions focusing on underage bettors.

Maine has proposed rules that might permit sports activities betting tv commercials to seem solely throughout dwell recreation broadcasts, which might be probably the most restrictive coverage within the nation. They would additionally prohibit commercials that provide betting bonuses and ban using “cartoon characters, professional or Olympic athletes, celebrities or entertainers” in advertisements.

Massachusetts final month formally banned advertising and marketing on school campuses and prohibited promoting geared toward minors. This month, it additionally joined New York in transferring to ban sports activities betting advertising and marketing outfits from getting paid a commission on bets positioned by patrons they ship to sports activities betting platforms, primarily based on a priority that these preparations may feed drawback playing.

Brian O’Dwyer, chairman of the New York State Gaming Commission, mentioned sports activities betting in his state was producing a windfall of tax income. But he added, “We have to make sure that we don’t hook people, we don’t promote problem gambling, and we certainly do not promote underage gambling.”

Maryland and Connecticut are individually transferring to ban betting firms from signing deals with public universities by which they pay colleges to assist them market their sports activities betting platforms.

“I think it is outrageous,” Connecticut State Representative Amy Morrin Bello, Democrat of Wethersfield, mentioned of the agreements that sure betting firms had signed with eight universities across the nation. Her invoice banning the offers handed this month by 142 to 0.

Ms. Morrin Bello and Mr. O’Dwyer mentioned their regulatory strikes have been prompted by reporting by The New York Times final yr on the explosive growth in sports betting within the United States, together with marketing on college campuses.

Ohio’s on line casino management fee has imposed greater than $800,000 in fines on sports activities betting firms since January. . The violators included DraftKings, one of the vital distinguished betting platforms, which acknowledged it illegally claimed bettors might make “free” bets and mistakenly mailed out 2,582 advertisements to state residents below the authorized betting age of 21, urging them to obtain its cellular app and declare $200 in free bets.

Penn Entertainment, one other main sports activities betting firm that operates below the model Barstool, was separately fined in February. Late final yr on the University of Toledo campus, Barstool hosted a college football present that promoted the corporate’s cellular sports activities betting utility regardless of a ban in promoting focusing on anybody youthful than 21.

Both firms declined to remark.

Mr. Schuler mentioned the enforcement had resulted in additional compliance from advertisers. But he mentioned he nonetheless had considerations, such because the betting firm logos affixed to gamers’ jerseys for the skilled soccer crew primarily based in Columbus, Ohio, a follow he referred to as “entirely offensive,” on condition that these gamers are heroes to many youths. “Their greed trumps the common sense that they should be employing when looking out for the harm to minors,” he mentioned, including that he doesn’t presently have the authority to ban betting sponsors from showing on jerseys.

The surge in abusive conduct focusing on school athletes {and professional} gamers has drawn consideration from coaches and the gamers themselves. Anthony Grant, the coach of the University of Dayton males’s basketball crew, condemned verbal and online attacks on his gamers from indignant bettors in January, simply days after Ohio legalized sports activities betting.

In a listening to final month in Illinois, Josh Whitman, the athletic director of the state’s flagship college, requested legislators to continue to prohibit the state’s sports activities books from accepting bets on in-state school sports activities. He introduced legislators with a letter, signed by representatives from lots of the state’s universities, that included five pages of crude and at instances racist remarks made on-line to gamers and groups.

Chris Boucher, a ahead for the N.B.A.’s Toronto Raptors, described on a podcast in March one of many hateful messages he acquired from a bettor. “I chose the wrong slave today,” the individual wrote to Mr. Boucher on social media after shedding his wager.

“In its purest form, players feel insulted that sometimes fans act as if players are playing for the purpose of them betting,” mentioned David Foster, the deputy normal counsel of the union that represents N.B.A. gamers. “When it crosses the line and becomes harassment and threatening, that’s even worse.”

While the particular language differs, laws or rule modifications proposed or accepted in Ohio, West Virginia and Massachusetts this yr would broadly permit state officers to bar bettors who threaten or harass athletes.

The business has supported the proposals, saying it abhors that sort of conduct towards athletes.

“There’s absolutely no place for that,” mentioned Casey Clark, a senior vp on the American Gaming Association, whose members embrace most main on line casino firms in addition to FanDuel and DraftKings. “And anybody taking their reaction to losing a bet to that extreme I think has a gambling problem and needs to seek help.”

The playing business {and professional} sports activities leagues have introduced their efforts to confront dangerous practices — and forestall additional obligatory tightening of guidelines.

That contains revisions to the American Gaming Association’s “responsible marketing code” endorsing the ban on the time period “risk free” bets and prohibiting advertising and marketing partnerships with schools. The skilled sports activities leagues and a few tv networks have joined to create what they’re calling the Coalition for Responsible Sports Betting Advertising, making statements like “sports betting should be marketed only to adults of legal betting age.”

Mr. Clark mentioned the business took steps to confront rising points earlier than regulators, reflecting a dedication “to provide the right kind of consumer protections that will enable a sustainable legal sports betting market.”

Brianne Doura-Schawohl, a lobbyist representing the National Council on Problem Gambling and different organizations, mentioned the transfer to tighten guidelines was a response to the sloppy job state officers did enacting legal guidelines legalizing sports activities betting in so many states since 2018.

“These are discussions that should have happened prior to legalization,” she mentioned.

The strikes abroad by regulators, Ms. Doura-Schawohl added, replicate what may very well be coming subsequent if the U.S. sports activities betting business doesn’t transfer quickly to go off issues which have emerged in international locations the place in some circumstances sports activities betting has been authorized for a few years.

Australia is preparing to ban using bank cards to position on-line bets, which now represent about 20 % of wagers. Belgium and the Netherlands, as of this summer time, will ban playing promoting on tv, radio, newspapers and in public areas.

“If you have untargeted advertisements — billboards and TV commercials — you can’t control who sees them, including young people and those with gambling problems,” mentioned Frerick Althof, a spokesman for the minister of authorized safety within the Netherlands.

Canada’s largest province, Ontario, last month proposed a ban on using athletes and celebrities in promoting, concluding that “potential harmful impact on the most vulnerable population, underage persons, remains high.” And within the United Kingdom, the federal government company that oversees on-line playing released a long-awaited study final month that concluded “change is needed now” as “gambling poses the risk of becoming a clinical addiction,” proposing “financial risk checks” for bettors who lose greater than $160 a month and endorsing a transfer to take away playing logos from the entrance of gamers’ shirts.

Mr. Clark, of the American Gaming Association, mentioned the playing business would object if a few of these strikes have been proposed within the United States, because it has to the pending limits on promoting on sports activities betting in Maine, which it considers excessive.

“We have always wanted to learn from more mature markets,” he mentioned, however added, “We don’t support restricting when we can market legal, regulated business.”