(CNN)— Sen. Barack Obama said Tuesday night evangelical leader James Dobson was “making stuff up,” when he accused the Illinois senator of distorting the Bible and taking a "fruitcake interpretation" of the U.S. Constitution.

“Any notion that I was distorting the Bible in that speech, I think anyone would be hard pressed to make that argument,” Obama told reporters on board his press plane Tuesday night.

Obama's past comments came front and center Tuesday when Dobson criticized the presumptive Democratic nominee’s June 2006 speech on his Focus on the Family radio show.

Watch: Schneider reports on Obama v. Dobson

In the speech, Obama suggested that it would be impractical to govern based solely on the word of the Bible, noting that some passages suggest slavery is permissible and eating shellfish is disgraceful.

Earlier: Evangelist accuses Obama of 'distorting' Bible

"Which passages of scripture should guide our public policy?" Obama asked in the speech. "Should we go with Leviticus, which suggests slavery is OK and that eating shellfish is an abomination? Or we could go with Deuteronomy, which suggests stoning your child if he strays from the faith? Or should we just stick to the Sermon on the Mount — a passage that is so radical that it's doubtful that our own Defense Department would survive its application?"

Obama responded Tuesday saying the speech underscored the notion he is a man of faith and highlighted the importance that people like him who find faith important “try to translate our concerns in a universal language so that we can have open and vigorous debate.”

UPDATE: Responding to the comments, Tom Minnery, senior vice president of Focus Action, said "There is no need to 'make stuff up' as it relates to Sen. Obama's interpretation of Scripture and the role of religion in the public square."

"His statements and record make clear his questionable perception of both. To argue that the Sermon on the Mount invalidates the Defense Department — as if Jesus Himself didn't have anything to say about the existence of good and evil and the need to combat evil — is about as deep as anyone needs to go to understand where the senator is coming from," Minnery also said. "He is editing God's word to fit his liberal worldview, and the more exposure his views on these matters get, the more obvious this will become to American Christians."

(CNN) – John McCain has effectively captured the Republican nomination, but he’s still struggling to win over a key constituency of one: Focus on the Family founder James Dobson, who once said he would not vote for the Arizona senator “under any circumstances.”

Some disappointed conservatives had threatened to stay home on Election Day – but Dobson’s interview Monday may send a message to millions of evangelicals that they should reconsider that decision and head to the polls.

In an interview last night, the evangelical leader told FOX host Sean Hannity that while he has issues with all the candidates left in the race, particularly the Democrats, he would definitely be casting his ballot this fall.

"Let me just say that I will certainly vote,” said Dobson. “I think we have a God-given responsibility to vote, and there are all of the candidates and the issues down the ballot that we have an obligation to weigh in on and let our voices be heard."

But he stopped short of embracing McCain’s presidential bid, and expressed skepticism about his orthodoxy on key conservative stands, asking Hannity skeptically if the senator had given a commitment on stem cell research.

Earlier in the race, Dobson backed McCain’s Republican rival, former Arkansas Gov. Mike Huckabee.

Dobson is urging social conservatives not to back a pro-choice candidate.

WASHINGTON (CNN) – James Dobson, a prominent social conservative leader, writes in The New York Times Thursday that conservative voters should not compromise their beliefs just to ensure that a candidate wins the election.

“Polls don’t measure right and wrong; voting according to the possibility of winning or losing can lead directly to the compromise of one’s principles,” Dobson wrote on the Op-Ed page of the newspaper.

“In the present political climate, it could result in the abandonment of cherished beliefs that conservative Christians have promoted and defended for decades.”

He added, “Winning the presidential election is vitally important, but not at the expense of what we hold most dear.”

At the very base, Dobson said a candidate should support “the sanctity of human life, the institution of marriage, and other inviolable pro-family principles.”

Dobson, who is the founder of Focus on the Family Action, also noted that at a recent meeting with social conservatives in Salt Lake City, there was near unanimity to support a minor party candidate” if none of the major candidates seeking the nomination support their political beliefs.

“After two hours of deliberation, we voted on a resolution that can be summarized as follows: If neither of the two major political parties nominates an individual who pledges himself or herself to the sanctity of human life, we will join others in voting for a minor-party candidate,” Dobson wrote. “Those agreeing with the proposition were invited to stand. The result was almost unanimous.”

Dobson’s threat not to back a candidate who supports a strict social conservative agenda appears to hurt former New York City Mayor Rudy Giuliani, a frontrunner for the GOP presidential nomination. But the Giuliani campaign has downplayed the potential threat of third party candidate, noting polls showing strong support for him among church-going evangelicals.

Asked Monday about the potential opposition from social conservatives, Giuliani reiterated his electablitity trump card.

"I run the most competitive against Hillary Clinton by a big big margin and I can take democratic states from her," he said. "Nobody else does that."

– CNN Ticker Producer Alexander Mooney