Republican senator Rand Paul sought to shore up his support among the religious right on Friday with a speech underlining his anti-abortion beliefs that contrasted with more permissive messages to recent liberal audiences.

Speaking at the Values Voter Summit, a conference hosted by the Christian-leaning Family Research Council in Washington, the future presidential hopeful suggested he would seek to protect the rights of unborn foetuses.

“I am one who will march for life and will continue to stand up in defence of life so long as I am in privileged to be in office,” he told the overwhelmingly conservative audience after a introductory video which featured the soundtrack of foetal heartbeat.

“The debate isn’t really about whether government has a role in protecting life; the debate really hinges on when life begins,” added Paul. “I’ve held one-and-half-pound babies in my hand.. don’t tell me that five- and six-pound babies have no rights simply because they are not yet born.”

His message that America was in a “spiritual crisis” and that “no civilisation can long endure that does not respect life” was little different from other leading Republicans speaking at the conference, such as Texas senator Ted Cruz.

However, the tone was noticeably different from April, when Paul spoke at the University of Chicago, during one of series of campus visits that have helped cement a growing popularity among younger voters. In that he distinguished clearly between his personal and legal beliefs, and suggested changing the law was not a top priority.

“My personal and religious belief is that life begins at the very beginning,” Paul told interviewer and former Obama adviser David Axelrod. “Where is the law going to be? I think the law could find something in between [that and where we are now]. Maybe there is an in-between … when the baby is able to react to pain, or viability.”

Crucially, Paul suggested he would not seek to change the law without a change in public opinion.

“I think where the country is, is somewhere in the middle, and we are not changing any of the laws until the country is persuaded otherwise,” said the senator.

At the time, the comments in Chicago drew criticism from the Family Research Council, which accused him of having a “nonchalant attitude on abortion and his role in ending it”.

Rand’s comments “certainly set off alarm bells for social conservatives” said FRC president Tony Perkins in a blog, adding: “Obviously, no president has the power to unilaterally ban abortion, but he does have the power to make the issue a priority – something most Americans assumed Rand Paul would do.”

On Friday in Washington, the differences were put behind them and Paul was introduced to the audience as a senator who had also voted against the Employment Non-Discrimination Act – legislation to prevent employers discriminating against gay workers that was opposed by some Christian conservatives for infringing on religious freedoms.

Such tension on social issues mirrors similar struggles faced by Senator Paul on national security where he has won support nationally for opposing excessive US military intervention overseas, but tried to reassure potentially Republican primary voters by calling for tough action against Islamic extremism.

The hawkish version was more evident at the Value Voter summit where other speakers warned of the threat of Islamic infiltration in the US and Texas lieutenant governor David Dewhurst claimed alleged prayer mats found in the brush nearer the Mexican border were a sign that Obama’s immigration policy was allowing terrorists to enter the country.

Senator Cruz was more hawkish still, railing against the administration’s decision to hold talks with Iran over nuclear weapons and accusing them of “sipping Chardonnay” together in New York during the recent United Nations general assembly – an image that may prove more metaphorical than actual given Iran’s ban on alcohol.