Hollywood-backed antipiracy legislation stalled out on Capitol Hill today, as Senate and House versions were delayed to come up with major changes to the bills.

Senate Majority Leader Harry Reid (D-Nev.) said that he is postponing a vote on a Senate version of antipiracy legislation, after a storm of protest and a defection of a number of supporters made it doubtful that he had the votes to get the bill to the floor.

Reid had stood firm on plans to hold a procedural vote on the PROTECT IP Act on Tuesday, but announced today that more time was needed to work out a compromise.

Reid said in a statement, “I admire the work that Chairman Leahy has put into this bill. I encourage him to continue engaging with all stakeholders to forge a balance between protecting Americans’ intellectual property, and maintaining openness and innovation on the internet. We made good progress through the discussions we’ve held in recent days, and I am optimistic that we can reach a compromise in the coming weeks.”

In the House, Judiciary Committee chairman Lamar Smith (R-Texas) said that the committee would postpone consideration of the Stop Online Piracy Act until there is wider agreement on a solution.

“The committee will continue work with both copyright owners and Internet companies to develop proposals that combat online piracy and protect America’s intellectual property,” Smith said. “We welcome input from all organizations and individuals who have an honest difference of opinion about how to address this widespread problem.”

He said that after hearing from critics, “It is clear that we need to revisit the approach on how best to address the problem of foreign thieves that steal and sell American inventions and products.”

One of the chief critics of the legislation in the House, Rep. Darrell Issa (R-Calif.), has introduced alternative legislation on which content owners could file complaints with the International Trade Commission to take steps to choke off support of sites that traffic in infringing content. But supporters of SOPA and PROTECT IP say that the proposal would expand the bureaucracy and that the remedy for fighting piracy would not be effective.

The response from Rupert Murdoch, via Twitter: “Mega loads! One week earlier and things would be different. Even some solons may have recovered their courage.”

Leahy said that he hopes “other members of Congress won’t simply stand on hollow promises to find a way to eliminate online theft by foreign rogue websites, and will instead work with me to send a bill to the President’s desk this year.”

But Leahy, perhaps the most visible champion of the legislation in Congress, had hoped that despite the online protest this week the Senate could have a vigorous floor debate on Tuesday.

He added that the “day will come when the Senators who forced this move will look back and realize they made a knee-jerk reaction to a monumental problem. Somewhere in China today, in Russia today, and in many other countries that do not respect American intellectual property, criminals who do nothing but peddle in counterfeit products and stolen American content are smugly watching how the United States Senate decided it was not even worth debating how to stop the overseas criminals from draining our economy.”