CLEVELAND >> Same-sex marriage and transgender rights are emerging as points of serious strain between social conservatives and moderates who are trying to shape the Republican platform, reviving a festering cultural dispute as thousands of party activists and delegates prepare for their convention.

Caught in the middle is Donald Trump, who claims “tremendous support, tremendous friendship” from gays, lesbians, bisexuals and transgender people, and has gone further than most party figures to embrace them. Gays, in fact, are one of the few minority groups Trump has not singled out for criticism. But as the presumptive Republican nominee, he is also trying to assuage doubts about the convictions of his conservatism.

The uncomfortable dynamic Trump has created for himself is perhaps best illustrated by his own calendar. He huddled last month at a Manhattan hotel with hundreds of religious conservatives, many of them — like James C. Dobson, founder of Focus on the Family, and Tony Perkins, president of the Family Research Council — outspoken opponents of new legal protections for gay and transgender people.

A few days later, he took what an aide described as a friendly and supportive call from Caitlyn Jenner, a former Olympic decathlete who came out as transgender last year.

One of the most contentious issues confronting delegates when they meet Monday to debate the platform will be whether to adopt a provision defending state laws that try to prevent transgender people from using the public restroom of their choice. At times Trump has criticized those laws. And he has said Jenner could use whatever bathroom she prefers at his properties.

But he has also promised not to interfere with the platform, which serves as the party’s official declaration of principles.

Even as Trump keeps his distance from the debate, other Republicans who share his more accepting view of gay and transgender issues are working aggressively to tone down some of the platform’s language.

The existing platform, adopted in 2012, is replete with disapproval of homosexuality.It calls court decisions favoring same-sex marriage “an assault on the foundations of our society” and accuses the Obama administration of trying to impose “the homosexual rights agenda” on foreign countries.

Paul E. Singer, a billionaire Republican who has financed gay rights battles across the country, is now funding an effort to write into the platform language more inclusive of gays, lesbians and transgender people. The goal of his group, the American Unity Fund, is not to get the party to endorse same-sex marriage but to add a more open-ended statement that commits the party “to respect for all families,” though there is still fierce resistance from the right.

“We don’t have to say we’re tolerant because we are tolerant of other views,” said James Bopp Jr., a member of the platform committee from Indiana who has long supported efforts to make the platform more strongly in favor of traditional marriage. Such language promoting tolerance, he added, would be “redundant and superfluous.”

Advisers for the American Unity Fund, who say they know they are fighting a steep uphill battle, argue that the Republican Party can no longer afford to alienate people on gay rights issues. “We’ve got to make room for people with diverse views on civil marriage,” said Tyler Deaton, the group’s senior adviser. “This platform doesn’t even make room for people who support civil unions or domestic partnerships or people who support basic legal equality.”

The Republican platform committee has long been dominated by some of the party’s most stalwart activists. And some of them have hardly been shy about their views.

There is Cynthia Dunbar of Virginia, who has compared the gay rights movement to Nazism. Hardy Billington, a committee member from Missouri, placed an ad in a local paper asserting that homosexuality kills people at two to three times the rate of smoking. And Mary Frances Forrester of North Carolina has claimed that the “homosexual agenda is trying to change the course of Western civilization.”

Bopp of Indiana recently wrote to delegates to say that the Republican Party has always opposed threats to traditional marriage “beginning with our opposition to the ‘twin relics of barbarism’ of slavery and polygamy in our 1856 platform.”

As dominant as those conservative voices have been, delegates who want to see a more inclusive platform are gaining seats on the committee.

Many of them believe the Republican Party needs to have a serious debate this year about whittling down a platform that has grown long and become riddled with special-interest additions.

Boyd Matheson, a first-time platform committee member from Utah, noted that at 33,000 words, the 2012 platform was “six or seven times longer than the Constitution.” Recent platforms have become, he said, “these laundry lists and litmus tests of ‘thou shalts’ and ‘thou shalt nots.’”

The party’s first platform in 1856 was less than 1,000 words.

As an alternative this year, Matheson proposed a 1,177-word document that he said adheres to the founding principles of the party, like equal rights and economic opportunity. It contains no mention of same-sex marriage or transgender issues. “That does not elevate the discussion we need,” Matheson said.

It is not the discussion Trump is eager to have, either. Asked in a recent interview about the platform, he declined to comment, saying only that he was “looking at it.”

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