A day before the Senate Judiciary Committee holds a hearing on the proposed merger between Comcast Corporation and its biggest rival, Time Warner Cable, Comcast filed a lengthy report with the Federal Communications Commission arguing that the proposed deal would benefit tens of millions of television viewers and Internet users. On its corporate Web site, Comcast promised, “Together, Comcast and Time Warner Cable will make life online better for more people by bringing faster Internet speeds, a more reliable and more secure network, low-cost Internet access, and programming diversity to millions of new customers across the country.”

Before you have a fit laughing, there’s more. In a blog post accompanying the filing, David L. Cohen, Comcast’s executive vice-president, disputed the widespread belief that his company is a rapacious monopoly, determined to tighten its grip on the markets for cable television, broadband access, and video-on-demand so that it can raise prices even further. “It’s understandable why any large merger will attract questions about competition and consolidation. But this particular transaction actually raises few competition concerns,” Cohen wrote.

Really? Comcast and Time Warner don’t compete against each other in any local market, Cohen pointed out, “so there is no reduction in consumer choice in any market.” Moreover, he went on, “The traditional boundaries between media, communications, and technology are obsolete. The competitive ecosystem in which we operate includes companies with national and even global scale—like AT&T, Verizon, DirecTV, DISH, Netflix, Amazon, Apple, Yahoo, Google, and Facebook—who are competing with each other and us in unprecedented ways.”

Poor Comcast—a humble enterprise “founded as a small company in Tupelo, MS,” as Cohen writes—is now besieged by competition from Jeff Bezos, Mark Zuckerberg, Sergey Brin, Tim Cook, the mighty Verizon, and a reborn Ma Bell. You might conclude, after reading Cohen’s note on the filing, that the Judiciary Committee should just cancel the hearing at which he is supposed to testify tomorrow, and tell Attorney General Eric Holder and Tom Wheeler, the former cable lobbyist who heads the F.C.C., to wave through the merger without further delay.

Or maybe not.

About the only one of Cohen’s statements that can’t be challenged is that combining Comcast and Time Warner won’t directly reduce the level of competition in many localities. But that’s only because the two companies already have monopoly cable franchises practically everywhere they operate. The competition is restricted to satellite-television providers, and, in some areas, A.T. & T., Verizon, and other phone companies that offer broadband “triple play” packages but that don’t really compete on price.

Indeed, far from vigorously challenging Comcast and other cable companies, the telcos have started doing deals with them to sell one another’s products. In many parts of the country, rather than building out their own fibre networks, which would be expensive, companies like Verizon are quietly coöperating with the cable companies—using their pipes to provide broadband Internet access, and splitting the profits. For the past decade or so, the F.C.C. has claimed to be pursuing a goal of “facilities-based competition”—competition based on separate delivery systems—but, with the onset of these deals, that goal is getting further away, not closer.

From a public-policy perspective, the question at hand is whether it would better to have two or three regional cable-broadband giants—that’s the current situation—or only one, in the form of Comcast-Time Warner. Traditionally, anti-trust authorities have considered mergers on the basis of the impact they are likely to have on prices. In this regard, Comcast’s submission to the F.C.C. was notably lacking any suggestion that the deal might lead to lower prices for consumers—despite the fact that the rates U.S. companies charge for cable and Internet services are very high by international standards. Rather than talking about lower prices, Cohen wrote, “The business reason for this transaction is to create the scale that will allow Comcast to make larger investments in R&D, innovation, and infrastructure to enable us to compete more effectively in this incredibly dynamic marketplace.”

Here, Cohen was presumably referring to the growing competition to cable television that is coming from online video—from new devices such as tablets and Roku boxes, and from providers like Netflix, Amazon, and Google. For cable customers who are tired of sending hefty payments every month for channels they don’t necessarily want, the rise of online video is, indeed, a promising development. But allowing Comcast to merge with Time Warner might serve to restrict its growth rather than promote it.

According to an analysis by the Consumer Federation of America, a combined Comcast-Time Warner company would have a dominant position in nineteen of the top twenty media markets. It would have about a third of all multi-channel video subscribers; it would control about half the high-speed Internet access in the country; and, through NBC-Universal, it would have an unrivalled slate of television channels and programming. With all these assets at its disposal, it would have enormous leverage that it could use to favor its own products and disadvantage those of competitors. What, exactly, could it do? In testimony he will deliver to the Judiciary Committee on Wednesday, Gene Kimmelman, the president of Public Knowledge, a Washington-based foundation, lists five ways that a combined Comcast-Time Warner could use its “unprecedented accumulation of market power”: