Senators had plenty of pointed questions for Comcast and Time Warner Cable executives today at a Capitol Hill hearing on their proposed mega-merger.

Members of the Senate Judiciary Committee pressed the execs on how a combination of the nation’s two largest cable companies would possibly benefit consumers.

The chairman of the committee, Sen. Patrick Leahy (D-VT), said, “Consumers … want to know why their cable bills are going up. They want to know why they do not have more choice of providers. Consumers are trying to find out whether and how this merger is good for them. I want to find out the same things.”

The senior Republican on the panel, Sen. Chuck Grassley (R-IA), said the merger has raised concerns about whether Comcast would be able to block consumers’ access to content, or put independent programmers at a disadvantage. “Most people would agree that we’re better off when Americans have a wide variety of programming options to choose from,” he said.

Comcast executive vice president David Cohen insisted that the merger was “pro-consumer and pro-competitive,” and the synergies and economic benefits of the deal would ultimately benefit consumers.

But Gene Kimmelman, the head of Public Knowledge (and formerly with Consumers Union), told senators, “This merger would give Comcast the incentive and ability to stifle competition, thwart innovation from online services, and impose higher costs on rival video and online services, which will eventually be paid for by consumers.”

Sen. Al Franken (D-MN) wasn’t persuaded by the companies’ arguments, either, saying he opposed the deal.  He noted that Comcast has 100 lobbyists deployed to lobby in favor of the merger, but that he had heard from 100,000 consumers who are against it.  He said he feared the deal would lead to higher prices, lower quality of service, and less choice for consumers.

At Consumers Union, we’ve heard the same thing from people all over the country.  Today we joined with other groups that have gathered petitions with 400,000 signatures urging the federal government to reject the deal.  The petitions will be delivered to the Federal Communications Commission and the Department of Justice, which will review the merger in the months ahead.

These petitions come on the heels of a letter from CU and more than 50 other public interest groups urging the FCC and Justice to block the deal.

If you agree that this merger is a bad deal for consumers, we hope you’ll sign our petition here.