IN 1911 the United States Supreme Court ruled that the American Tobacco Company was “an attempt to monopolise” trade and ordered its break-up. Now two of the four companies that came out of the dismantled monopoly are recombining. On July 15th Reynolds American, the country’s second-largest cigarette-maker, said it would pay $27.4 billion in cash and shares to take over Lorillard, the third-biggest. The merger shakes up the world’s third-largest market by volume (behind China and Russia) and will have reverberations overseas.

The biggest question is whether today’s trustbusters will let it happen. One might expect them to be indifferent. Why should they worry if oligopolistic tobacco giants raise prices, discouraging smokers from indulging in a habit that might kill them? In fact the Federal Trade Commission (FTC) regards nicotine addicts as an especially vulnerable group of consumers. That will make it more difficult to get the merger through, says David Balto, an antitrust lawyer who worked at the FTC.

That explains the presence of a third party to the merger. Imperial Tobacco of Britain will buy a clutch of brands from the merging couple, including Winston, a struggling “premium” cigarette that competes with Marlboro, the market leader, and Blu, the best-selling American e-cigarette. The deal will turn Imperial, now a marginal presence in America, into a credible number three, with a market share of about 10%. With Lorillard, Reynolds will be a stronger challenger to Altria, Marlboro’s maker. The merger is “pro-competitive”, insists Murray Kessler, Lorillard’s boss.

Perhaps, but Lorillard was a feisty competitor, forcing its bigger rivals to restrain price increases. Mr Balto wonders whether Imperial will fill that role. That does not seem to be the ambition of its chief executive, Alison Cooper. Part of America’s appeal is that cigarettes are relatively cheap there, she says. That leaves “plenty of opportunity for price-led profit growth”.

For Reynolds and Lorillard, the merger is a way to continue delivering rising profits to shareholders in a market where consumption is dropping by 3% a year. The main prize for Reynolds is Newport, a menthol-flavoured cigarette popular with black and Hispanic smokers, and one of the few whose sales volume is growing. Reynolds’s sales force will now pack America’s second-biggest brand alongside Camel and Pall Mall in their sample cases. That will make it more efficient to distribute to America’s innumerable tobacconists and will boost sales in the West, where Newport is relatively weak. Ambitiously, the merged company also hopes to save $800m a year by combining some operations and selling others to Imperial.

It may be a first step towards ending America’s relative isolation from the global tobacco market. Foreign companies kept their distance (and Altria spun off Philip Morris International in 2008) in part because no one knew how much American courts would make tobacco firms pay to people who got sick from using their products. Those costs now look more predictable, making it safer for firms like Imperial—which is acquiring only brands, not liability-bearing legal entities—to come back into the market.

British American Tobacco, Reynolds’s biggest shareholder, will pay $4.7 billion to maintain its 42% share. There is speculation that it will eventually buy the whole company. In the meantime the duo will collaborate on what some see as the future of smoking: less-dangerous e-cigarettes and cigarettes that heat tobacco rather than burn it. They might also market conventional brands like Newport overseas, suggests Shane MacGuill of Euromonitor International, a market-research firm.

The main holdout against tobacco globalisation is now China, which accounts for about 40% of the cigarettes smoked, almost all of them sold by state-owned China Tobacco. Erik Bloomquist, an analyst at Berenberg, a bank, thinks the Chinese giant could someday acquire one of the big international firms. A deal like that would probably be the last gasp in the round of tobacco consolidation.