(CNSNews.com) - A liberal advocacy group is organizing "Constitution Vigils" on Wednesday to prod Congress to investigate President Bush's alleged "lawbreaking" in connection with the National Security Agency surveillance program.

"We believe that public pressure will force Congress to take this seriously," MoveOn.org said in an email message to supporters.

"When our elected officials are home for the President's Day break, they need to see the faces of people in their community who expect them to hold the president accountable. If thousands of us come together, we'll give Congress the push they need to go all the way."

MoveOn.org is urging Bush opponents to either attend or host one of many "vigils" taking place across the country on Wednesday, Feb. 22.

"At each vigil, we'll get together with other MoveOn members and supporters from the ACLU and People for the American Way to read the Bill of Rights to remind Congress about what's at stake and that it's their job to defend the Constitution. And, we'll invite the media and get our message out to millions of Americans," MoveOn.org said.

MoveOn.org said a Justice Department review of the NSA surveillance program is a start - but it's not enough. It wants Congress to also investigate the president's "dangerous power grab."

MoveOn.org is telling supporters that the Bush administration is "nervous" about what an investigation will find and is therefore pressuring Republicans to "back off." It quotes press reports saying that the Bush administration is lobbying against a congressional probe of the NSA program.

"By attending a vigil on the 22nd, you'll be sending a clear message to your elected officials: they need to do their job, defend the Constitution and hold the president accountable, and you're watching to make sure they do," MoveOn.org concluded.