The merger floodgates broke open five years ago, and now U.S. Senator Elizabeth Warren wants to close the hatch.

Her proposed bill to substantially restrict big corporate tie-ups is more a presidential campaign statement than viable legislation — and it certainly won’t score her any more points with the Wall Street crowd — but she is calling attention to the maniacal pace of dealmaking in corporate America and the need to modernize antitrust laws that have permitted some recent problematic transactions.

More than $7 trillion of takeovers of U.S. companies have been announced since this day in 2014 — 52,694 companies to be exact. That compares with just $4.4 trillion of deals in the previous five-year period. The transactions grew over time as balance sheets flush with cash and income statements desperate for growth created a perfect storm, which more often than not was stoked by pliable regulators.

The Walt Disney Co. acquired 21st Century Fox Inc.; Charter Communications Inc. bought Time Warner Cable Inc.; CVS Health Corp. took over Aetna Inc.; Marriott International Inc. merged with Starwood Hotels & Resorts Worldwide Inc.; and T-Mobile US Inc. is trying to buy Sprint Corp. Those are just some of the more recognizable names. 

Warren, one of the top-polling candidates heading into the Democratic primaries, wants to ban deals in which one company has annual revenue of more than $40 billion, or both businesses generate more than $15 billion in sales, according to a draft of the bill reviewed by Bloomberg News. (A notable exception would be companies facing insolvency.) That could effectively prevent every top airline, insurer, manufacturer, oil producer, retailer, technology platform and other conglomerates — perhaps even Warren Buffett’s M&A vehicle, Berkshire Hathaway Inc. — from making any acquisitions. It would sound the M&A death knell. The idea, however, is unlikely to gain broad support among lawmakers.

Even so, it’s hard not to notice the rising drumbeat of politicians concerned about overreach by corporate giants, particularly those in the tech field. Senator Amy Klobuchar, another Democratic presidential candidate, plans to introduce separate antitrust legislation soon, Bloomberg News reported, citing a person familiar with the matter. (Michael Bloomberg, the founder and majority owner of Bloomberg LP, the parent of Bloomberg News and Bloomberg Opinion, is also campaigning for president.)

For the Trump administration’s part, the U.S. Justice Department is already investigating whether tech giants — namely Apple Inc., Amazon.com Inc., Facebook Inc. and Google — are using their unchecked power to engage in harmful business practices. But as I wrote in July, if regulators are so concerned about protecting consumers from tech overreach, their glowing endorsement of T-Mobile’s takeover of Sprint is a funny way of showing it; it will shrink the U.S. wireless market from four to three major carriers and remove a company that’s helped to keep customer prices in check.

Antitrust regulation under President Donald Trump has at times created questionable optics. Makan Delrahim, the Justice Department’s top antitrust enforcer, seemed to switch his stance on AT&T Inc.’s takeover of Time Warner Inc. as Trump railed against the deal. Time Warner was the parent of CNN, which Trump views as his personal nemesis. (I’ve argued that whatever the case, scrutiny of the megamerger was warranted considering the broad market power it gave to AT&T as media companies without such scale struggle to compete.) By comparison, Disney and Fox, which was controlled by Trump pal Rupert Murdoch, closed their megadeal with few regulatory hiccups. 

Warren has criticized other giant deals, such as the merger of SunTrust Banks Inc. and BB&T Corp. and the combination of seed makers Bayer AG and Monsanto Co. Given that they aren’t household names, though, most Americans are unfazed by or unaware of such deals, even though they may feel the effects later. Her bill would direct the government to take into account not just whether a merger will lead to higher prices but also what the impact might be on workers, privacy and industry innovation. To justify the cost of buying another large company, dealmakers tend to come up with ambitious estimates of synergies, a euphemism for layoffs. 

It’s clear that the meaning of “harm” needs to be expanded in the antitrust sense, and laws need to take a more holistic view of the potential consequences of M&A as the lines between industries continue to blur. The Big Tech factor also needs to be weighed, as some deals are being done in part to respond to companies like Amazon that are spreading their tentacles into new areas. On Wednesday, TV-network operators CBS Corp. and Viacom Inc. completed their own merger, a bid to cut costs and create more scale to compete against a new roster of even more powerful media giants: Amazon, Apple, AT&T and Disney. Even then, ViacomCBS Inc., as the merged entity is now called, may not be big enough, and so it may be only a matter of time before it gets swallowed. 

Warren’s overly broad proposal likely isn’t the answer. But Democrats do seem ready to at least try to rein in a market that’s gotten out of hand. For dealmakers, this may be last call at the M&A party.

Tara Lachapelle is a Bloomberg Opinion columnist covering the business of entertainment and telecommunications, as well as broader deals. She previously wrote an M&A column for Bloomberg News.