Donald Trump rallied the faithful on Friday in a speech that aimed to shore up support among religious conservatives as his popularity haemorrhages elsewhere.

Becoming the first sitting president to address the annual Values Voter Summit, Trump entered a ballroom at the Omni Shoreham Hotel in Washington to applause, cheers and chants of “USA! USA!”

He proceeded to cast himself as a man of God.

“Everyone here today is brought together by the same shared and timeless values,” said the thrice-married socialite and reality TV star who was once recorded bragging about grabbing women “by the pussy”, yet who gained strong backing from Christian evangelicals in last November’s election. “We cherish the sacred dignity of every human life.

“We believe in strong families and safe communities. We honour the dignity of work. We defend our constitution. We protect religious liberty. We treasure our freedom, we are proud of our history, we support the rule of law and the incredible men and women of law enforcement. We celebrate our heroes and we salute every American who wears the uniform. We respect our great American flag.”

This last point brought conference delegates to their feet amid whoops and whistles, making clear where their sympathies lie in the dispute between Trump and football players who “take a knee” during the national anthem in protest over racial injustice and police brutality.

The president hit further applause lines in a room that had earlier been treated to a speaker wearing an industrial apron in order to “drain the swamp” and an unflattering photo of Hillary Clinton shown for the purpose of mockery. A panel featuring three Republican members of Congress had praised Trump’s attempt to ban transgender people in the military and urged tougher restrictions on abortion. The Values Voter summit is sponsored by the conservative Family Research Council.

Trump was happy to embrace a siege mentality among some evangelicals who claim they are marginalised by liberal media and a Hollywood-dominated culture. The founders invoked “our creator” four times in the declaration of independence, he said. “How times have changed. But you know what? Now, they’re changing back again. Just remember that.”

Since taking office in January “we have followed through on one promise after another,” Trump claimed. “I didn’t have a schedule, but if I did have a schedule I would say we are substantially ahead of schedule.”

He has not passed any major legislation in that time but, he reminded the audience, he did nominate Neil Gorsuch to the supreme court, a conservative “in the mould” of Antonin Scalia who died in February 2016. The vacancy was a critical factor in the election for many religious conservatives, the need to prevent a Clinton nominee overriding concerns about Trump.

The president insisted that he was “stopping cold” attacks on Judeo-Christian values and was determined to protect religious liberty. “We will not allow government workers to censor sermons or target our pastors, our ministers, our rabbis,” he said. “These are the people we want to hear from, and they’re not going to be silenced any longer.”

He also declared an end to the “war on Christmas”, a favourite theme of conservative media outlets such as Fox News.

“As we approach the end of the year, you know, we’re getting near that beautiful Christmas season that people don’t talk about any more. They don’t use the word ‘Christmas’ because it’s not politically correct. You go to department stores and they’ll say ‘Happy New Year’ and they’ll say other things. And it’ll be red, they’ll have it painted, but they don’t say – well, guess what? We’re saying ‘Merry Christmas’ again.”

He mentioned his hope that Congress will give the American people a Christmas gift by passing his tax cut proposal but chided members over their failure to pass a healthcare bill, saying “they forgot what their pledges were”.

Turning to foreign policy, Trump told the audience: “Above all else, we know this. In America we don’t worship government. We worship God. Inspired by that conviction, we are returning moral clarity to our view of the world and the many grave challenges we face.”

He again used the phrase “radical Islamic terrorism”, one that Barack Obama studiously avoided, to cheers and applause, and made the questionable assertion: “We’ve done more against Isis in nine months than the previous administration’s done during its whole administration – by far, by far.”

Eight in 10 white evangelicals cast their vote for Trump last November, according to exit polls – a higher proportion than supported fellow Republicans George W Bush in 2004, John McCain in 2008 or Mitt Romney in 2012. The constituency is vital for Trump, whose approval has dipped even in red states such as Tennessee (-23 percentage points), Mississippi (-21) and Kentucky (-20), according to a Morning Consult survey published this week.

Earlier in the speech, he paid tribute to victims of the mass shooting in Las Vegas, fires in California and hurricanes in Texas, Florida, Puerto Rico and the US Virgin Islands.

But he mistakenly said he had spoken to “the president” of the Virgin Islands. The president of that US territory is Trump himself.

