Political support for SOPA was seriously reduced yesterday by the concerted efforts of citizens, and not by huge political contributions and lobbying. It is a true voter uprising.

Phone calls and e-mail messages poured in to Congressional offices against the Stop Online Piracy Act in the House and the Protect I.P. Act in the Senate. One by one, prominent backers of the bills dropped off.

First, Senator Marco Rubio of Florida, a rising Republican star, took to Facebook, one of the vehicles for promoting opposition, to renounce a bill he had co-sponsored. Senator John Cornyn of Texas, who leads the G.O.P.’s Senate campaign efforts, used Facebook to urge his colleagues to slow the bill down. Senator Jim DeMint, Republican of South Carolina and a Tea Party favorite, announced his opposition on Twitter, which was already boiling over with anti-#SOPA and #PIPA fever.

Then trickle turned to flood — adding Senators Mark Kirk of Illinois and Roy Blunt of Missouri, and Representatives Lee Terry of Nebraska and Ben Quayle of Arizona. At least 10 senators and nearly twice that many House members announced their opposition.

Of course, Hollywood has tremendous financial resources so a one-day protest does not guarantee any particular result. We must keep the pressure on going forward.