Presidential candidate Senator Ted Cruz tried to mark himself out from other Republican hopefuls by telling a gathering of 600 evangelical pastors in Washington DC that he would "always, always stand and fight for religious liberty".

Speaking at the Watchmen on the Wall conference yesterday, an event sponsored by the Family Research Council, he attacked the Democrats for an agenda that prioritised gay rights ahead of religious liberty.

"The modern Democratic Party has become so radical, so extreme, that they have determined that their devotion to mandatory gay marriage in all 50 states trumps any allegiance to religious liberty under the First Amendment," Cruz said.

He said religious freedom was the foundational liberty on which America was built, and described it as a liberty now under assault, referring to the "battles" in Indiana and Arkansas over the religious liberty laws.

And Cruz didn't just accuse Democrats of undermining freedom on these issues; many Republicans for also "ran for the hills", he said. "Some of the Republicans running in 2016 were nowhere to be found when Indiana was being fought."

His subsequent assurance that he would "always, always, always stand and fight for religious liberty of every American" was met with rapturous applause from the audience – and someone even started blowing a shofar.

However, Cruz did acknowledge that the challenges to religious liberty in America paled in comparison with the violation of freedoms across the globe.

He described ISIS as the "face of evil" and attacked President Obama's response, saying: "You cannot win a war on radical Islamic terrorism with a president who is unwilling to utter the words, radical Islamic terrorism."

Referring to the story of Sudanese woman Meriam Ibrahim, who was sentenced to death for her faith, he said "very few of us have been faced with a hundred lashes and execution for believing in Jesus."

"Compared with that, problems in America don't seem all that bad," Cruz said as an encouragement. He also reiterated a call for Christians in America to turn up and vote if they want to see change in the nation.

"We've got an obligation, as this conference recognizes, to be watchmen on the wall," he said.