"After the eight years of the Bush administration policies, our economy was driven into the ditch. And for the past 20 months, our Republican colleagues have been carping and criticizing every effort we've made to get the economy out of the ditch and back in gear," he added.
Bashing the Obama administration's economic agenda was the theme of the Americans for Prosperity's Foundation annual conference today. The event boasted an attendance of 2,500 -- the highest ever for the event since it began four years ago.
Virginia Gov. Bob McDonnell pushed attendees to fight for "federalism and limited government."
"Democracy is not a spectator sport. I call you to action," he said. "Fight for those principles back home, because there's an awful lot at stake in this country."
AFP president Tim Phillips dismissed Democrats' criticism as "petty attacks."
"We're winning and you know you're winning when the other side is reduced to just petty attacks," he said. In November, "I think you're going to see a political tidal wave that changes the direction of this country, and specifically, it's going to be a repudiation of Speaker Pelosi and President Obama's big government big spending policies."
The National Park Service estimates about a 100,000 people will be in attendance today at Beck's rally. The DC Homeland Security and Emergency Management Agency (HSEMA) is preparing for a crowd of between 100,000 and 200,000 for all rallies taking place in the nation's capital today.
ABC News' John Parkinson and Tahman Bradley contributed to this report.