The Senate employed a rare device Wednesday, voting to rescind new media ownership rules approved by the Federal Communications Commission (search) that would make it easier for corporations to expand their markets and cross ownership of print and broadcast outlets.

The Senate voted 55-40 to support a "resolution of disapproval" of new rules approved by the FCC in June. While Democrats lost a couple votes — Sens. Zell Miller of Georgia and John Breaux of Louisiana — and Sens. John Kerry of Massachusetts and John Edwards of North Carolina were on the campaign trail rather than the Senate floor, they managed to pick up 12 Republican votes.

"We have to ensure that the marketplace of ideas is not dominated by a few conglomerates at the expense of our citizens and our democracy," Sen. Patty Murray, D-Wash., said before the vote.

To be enacted, the measure — also called a "congressional veto" — would still have to pass the House and be approved by President Bush. The White House has threatened to veto the legislation.

Sens. Byron Dorgan of North Dakota and Trent Lott of Mississippi, sponsors of the legislation, said they believe the House would approve the measure. Lott said he believed it would be a "big mistake" for the president to veto it.

Sen. John McCain, R-Ariz., said he opposed the resolution because it was too broad.

"This action would invalidate both good and bad," McCain said, and added he supports restoring limits on national TV station ownership.

Critics of the new rules say they fear that easing media ownership would concentrate power and ideas as well as jeopardize the future of free TV.

Gene Kimmelman, senior policy director for Consumers Union (search), publisher of Consumer Reports magazine, said the major TV networks don't need the help.

"Free TV and pay TV are completely intertwined," he said Monday. "A handful of corporations own and control the vast majority of both."

In June, the Republican-dominated FCC voted 3-2 along party lines to ease the decades-old ownership restrictions. The changes included allowing a single company to own TV stations reaching nearly half the nation's viewers and combinations of newspapers and broadcast outlets in the same area.

FCC Chairman Michael Powell (search) said the old rules made it harder for broadcast networks to compete with cable and satellite subscription services, and the risks to free TV is part of the reason the agency relaxed the rules.

Major media companies said the changes were needed because the old regulations hindered their ability to grow and compete in a market altered by cable television, satellite broadcasting and the Internet.

But lawmakers from both parties and a broad range of groups criticized the changes, saying they could lead to a wave of mergers and ultimately stifle diversity and local viewpoints in news and entertainment.

On Sept. 3, a federal appeals court in Philadelphia temporarily blocked the rules from taking effect the following day as scheduled. Several other legal challenges to the rules from broadcasters and consumer groups are pending.

The Senate resolution is a legislative maneuver, also called a "congressional veto," that has been used successfully only once before. In 2001, the Republican-controlled Congress and White House used it to repeal workplace safety regulations issued late in the Clinton administration.

If the president vetoes the legislation, the House and Senate will need to come up with two-thirds support for overriding it, a threshold that would be difficult to cross.

The House dealt the FCC a surprising setback in July when it passed a broad spending bill that included a provision to block the commission from allowing individual companies to own TV stations reaching up to 45 percent of the nation's viewers, instead of the current 35 percent. The Senate Appropriations Committee approved a similar measure last week.

Before the House vote, the White House also threatened to veto any final bill containing language that would roll back the national cap. Republicans who support the new rules hope that threat will help them strip the provision from a final House-Senate compromise bill.

Fox News' Julie Asher and The Associated Press contributed to this report.