Reverend Franklin Graham has officially kicked off his Decision America Tour, and one of the first things he did was to encourage Christians to vote for leaders "who will lead this nation back to really be one nation under God."

"Well, I'm here to say today I'm not going without a fight," he told an estimated crowd of about 2,500 at the Iowa Capitol in Des Moines on Tuesday, according to the Citizen Times.

"Secularism and communism, there's no difference," he said, adding that the government "has come from God and secularists are wanting to take it away."

Just a few weeks ago, Graham announced that he was leaving the Republican Party after the U.S. Congress passed a $1.1 trillion spending bill last month that includes funds for Planned Parenthood, which President Obama immediately signed into law.

He said his move was not to inspire other evangelicals to bolt the party as well, triggering a mass exodus, explaining that he simply wanted to focus on God and prayer during the 2016 national elections.

During his tour, Graham asked his audience to sign a pledge that calls on them to support "candidates who will uphold biblical principles, including the sanctity of life and the sacredness of marriage."

"Let's elect men and women to office who will lead this nation back to really be one nation under God, that can truthfully say once again, 'In God we trust,' " Graham said.

Meanwhile on his Facebook page, Graham described the start of the tour as "exciting."

"I was moved to see hundreds of people come out in the bitter cold to join me in praying for God to heal our land," he wrote. "Over 2,500 — men, women, and children, people of all ages realising the urgency of this critical time in our nation's history — were willing to take a bold stand for God."

"We need to vote, and we need to elect men and women to office who will lead this nation back to 'one nation under God'," he said. "The truth is, unless America turns back to God and repents of its sin and experiences a spiritual revival, we will fail as a nation."