Onstage, jazz vocalist Rene Marie is spontaneous, feisty and soulful, dressed with a charismatic flair. Those who see her Tuesday at the Dakota Jazz Club might have trouble imagining this galvanizing 55-year-old woman with the strict member of the Jehovah's Witnesses who went door-to-door back in the 1970s and '80s, religious tracts in hand. But she says one wouldn't exist without the other.

"I learned to think on my feet when I was a Witness, because you never knew what was on the other side of that door," she said by phone from California, where she was on tour with her trio. "I learned to be patient and respect people when they expressed themselves. And I learned it isn't about agreeing -- some people agree with you just to get you out the door -- as much as feeling you've made a connection.

"That is my goal singing live and composing; to get past all the layers we cover ourselves up with every day and touch that emotional G-spot that is in all of us."

Son pushed her to sing

That quest has required an enormous amount of willpower. After being a Witness from age 18 to her mid-40s, Marie left the church and her husband to launch a singing career, encouraged by her then-college-aged son Michael. And after enjoying a commercially successful four-record relationship with the MaxJazz label in 2004, she struck out on her own.

In 2007, she self-released the album "Experiment in Truth," donating one of its songs to the Colorado Coalition for the Homeless, and cutting another single, "Three Nooses Hanging," protesting an act of racial intimidation in Jena, La. Two years later, she self-released the soundtrack to a one-woman play she wrote and performed in her adopted hometown near Denver, titled "Slut Energy Theory," dealing with, among other things, domestic abuse.

In between there was a national controversy stirred when she sang the words to "Lift Ev'ry Voice and Sing" -- commonly referred to as "The Black National Anthem" -- to the tune of "The Star Spangled Banner" before a State of the City address by Denver's mayor.

"I wish I could share all the e-mails I got," said Marie, sounding sincerely grateful to have touched so many emotional G-spots. "Some were violently upset, some were tearfully grateful, and some were genuinely confused. It was a very nice cross section of America, and I was so touched by all of it. Just like you can't pick your family, you can't choose your countrymen and bend them to your will."

As far back as her second record, Marie did a racially fraught medley of an affectionate Southern anthem ("Dixie") with a song about black lynchings ("Strange Fruit").

Despite all the topical tumult she has pursued through her music, Marie insists that her engagement is "not because of any political thought; it is always from an emotional response." But isn't she an avid admirer of the late-singer Nina Simone, renowned for her fiery political stands? "I admire Nina because she didn't let anyone get in the way of her musical expression," Marie replied.

This is her 'Country'

Last year, she signed a two-record deal with the Motema label and will devote much of her Dakota show to the material on those discs.

The first, a collection of cover tunes and thematically ambitious song clusters titled "Voice of My Beautiful Country," was released a few months ago. It contains the controversial melding of anthems she sang in Denver, along with "My Country 'Tis of Thee" and "America the Beautiful." But there is also a full-throated rendition of Jefferson Airplane's drug-laden "White Rabbit," and a gorgeous linking of the 1950s jazz standard "Imagination" with a wistful-then-gospel rendition of the Temptations' "Just My Imagination."

Marie also promises "a little tease" from the second record, "Black Lace, Freudian Slip," which contains nearly all original material and will be released this fall.

"It crosses a lot of genres, including hillbilly music, because I grew up around the Blue Ridge Mountains," she enthused. "I am especially thrilled about a song my son Michael wrote, a haunting tune that comes from deep in the mountains. He is the one who convinced me to start singing [professionally], so this song comes full circle."

Expect gusto and a generosity of spirit from Marie at the Dakota. During her days of going door-to-door, "I tried never to forget that I was an uninvited guest in their homes." Similarly, when she performs, "People have paid and come to hear me sing, and that is something that is never far from my mind."