If approved, the proposed merger would create a powerful new force in the country’s broadband market. The combined company would rank as the country’s second-largest broadband provider behind Comcast with about 19.4 million subscribers, and the country’s No. 3 video provider with 17.3 million customers, across about 40 states. That increased heft is coming under close scrutiny as federal regulators continue their review of the Charter deals. If approved, the merger would most likely include strong conditions meant to prevent Charter from leveraging its market power to hurt rival streaming services, regulatory experts said. With increased clout, for instance, the company could restrict television networks from selling their content through stand-alone streaming services.

Charter, which already has announced a number of commitments related to the merger, has extra incentive to agree to conditions. Time Warner Cable would receive a breakup fee of up to $2 billion if the transaction falls apart. The company received nothing when Comcast walked away from its deal.

Another prominent issue is the role and influence of John C. Malone, the media mogul whose company Liberty Broadband would hold a 20 percent stake in a reconstituted Charter. Some groups have called for regulators to place restrictions on the involvement of Mr. Malone, saying that his interests in entertainment companies — including Discovery Communications and Starz — could represent untenable conflicts. Whit Clay, a spokesman for the Liberty businesses, declined to comment.

Charter has argued that its deals pose no threat to the online video market because the future of its business depends more on broadband than its legacy video business. Alex Dudley, a Charter spokesman, said in a statement that the company is committed to creating American jobs, offering innovative products, faster Internet speeds, preserving an open Internet and online video with no data caps or modem fees.

“It should come as no surprise that Dish and other parties seeking to use the regulatory review process to extract concessions are also engaging in tired P.R. tactics to further their self-interests,” Mr. Dudley said in a statement. “Their arguments against the pending transactions are baseless.”