US Representative Katherine Harris told a religious journal that separation of church and state is "a lie" and God and America's founding fathers did not intend the country to be "a nation of secular laws."
The Republican candidate for US Senate also said that if Christians are not elected, politicians will "legislate sin," including abortion and gay marriage.
Harris made the comments -- which she clarified on Saturday -- in the Florida Baptist Witness, the weekly journal of the Florida Baptist State Convention, which interviewed political candidates and asked them about religion and their positions on issues.
Separation of church and state is "a lie we have been told," Harris said in the interview, published on Thursday, saying separating religion and politics is "wrong because God is the one who chooses our rulers."
"If you're not electing Christians, then in essence you are going to legislate sin," Harris said.
Her comments drew criticism, including some from fellow Republicans who called them offensive and not representative of the party.
Florida Representative Debbie Schultz, a Democrat who is Jewish, told the Orlando Sentinel that she was "disgusted" by the comments.
Harris' campaign released a statement on Saturday saying she had been "speaking to a Christian audience, addressing a common misperception that people of faith should not be actively involved in government."
The statement said Harris' comments reflected "her deep grounding in Judeo-Christian values," adding that she had previously supported pro-Israel legislation and legislation recognizing the Holocaust.
Harris' opponents in the Republican primary also gave interviews to the Florida Baptist Witness but made more general statements on their faith.
Harris, 49, faced widespread criticism for her role overseeing the 2000 presidential recount as Florida's secretary of state.
State Republican leaders -- including Governor Jeb Bush -- do not think she can win against Democratic Senator Bill Nelson in November.
Fundraising has lagged, frustrated campaign workers have defected in droves and the issues have been overshadowed by news of Harris' dealings with a corrupt defense contractor who allegedly gave her US$32,000 in illegal campaign contributions. She denies the charges.