WASHINGTON — Glenn Beck, a hero of the political right and the closing speaker at a conference of political conservatives here, offered a sweeping denunciation of progressivism on Saturday, calling it a cancer that must be cut out of the nation’s political system.

Blaming President Obama for the nation’s problems was “too simple an answer,” Mr. Beck, a popular conservative talk show host, told thousands of cheering supporters at the annual meeting of the Conservative Political Action Conference. The real problem, he said, is progressivism, scrawling the word with chalk on a portable blackboard, a prop from his television show. “This is the disease in America,” he said.

But Mr. Beck aimed his fire at Republicans, too, giving them little quarter and saying he did not know what the party stood for. Mr. Beck, along with Newt Gingrich, the former House speaker who led the Republican revolution in 1994, were among those who championed limited government and lower taxes at the three-day gathering of influential conservatives.

Mr. Beck, a recovering alcoholic, drew a parallel to addiction recovery programs and said that the Republican Party had to admit it was in trouble.