When Fox News and talk radio host Glenn Beck comes to Washington this weekend to headline a rally intended to "restore honor" to America, he will test the strength - and potentially expose the weaknesses - of a conservative grass-roots movement that remains an unpredictable force in the country's politics.
Beck, who is both admired and assailed for his faith-based patriotism and his brash criticism of President Obama, plans in part to celebrate Martin Luther King Jr. as an American hero. He will speak on the anniversary of the "I Have a Dream" speech, from the spot where King delivered it.
Some "tea party" activists say the event, at which former Alaska governor Sarah Palin is also scheduled to speak, will have a greater impact than last September's "9/12" march along Pennsylvania Avenue. Though the attendance figures for that anti-tax rally are disputed, it was the first national gathering to demonstrate the size and influence of the tea party movement.
But with just a few days before the Beck rally, basic questions linger, including how big it will be and whether the event, which Beck says is nonpolitical, will help or hurt Republicans in November. Also unanswered is whether Beck can pull off the connection to King without creating offense - or confrontation with another event the same day led by the Rev. Al Sharpton.
Glenn Beck rally will be a measure of the tea party's strength