Donald Trump’s former primary opponents Ted Cruz and Marco Rubio are both among a group of Republican Senators who have publicly urged him to sign an anti-LGBT religious freedom order.

A draft executive order leaked from inside the White House earlier this year that would actively permit religious discrimination against LGBT people.

The leaked order would protect people who discriminate based on “the belief that marriage is or should be recognised as the union of one man and one woman [or that] male and female refer to an individual’s immutable biological sex as objectively determined by anatomy at birth”.

After the document leaked and sparked immediate protests, White House officials claimed it had been spiked – but insiders say it is still secretly being worked on, and is being re-drafted to make it less vulnerable to a legal challenge.

The order was confirmed to be back under consideration this week, as 18 Republican Senators signed a letter to Trump urging him to sign it.

The letter was released by the Family Research Council, as noticed by Joe My God.

Citing the 2015 court ruling that brought about equal marriage, the letter claims that “an executive order requiring federal government agencies to protect the right to religious freedom is necessary”.

It asserts: “Highly-qualified faith-based organisations are being denied or they are declining to compete for federal contracts and grants because of their religious beliefs. (…) The threat of loss of accreditation or charitable tax status lingers in the wake of the United States Solicitor General’s comments upon the Supreme Court’s 2015 ruling in Obergefell v Hodges that the loss of charitable tax status was ‘certainly going to be an issue’.”

The letter continues: “We cannot be a country that financially punishes individuals for practising their sincerely held religious beliefs or decides which practices are a valid part of a particular religious tradition and worthy of protection.

“We appreciate your consideration of this request and look forward to working with you on this vital issue.”

The letter was signed by 18 Republican Senators – Senators Roy Blunt (Mo.), James Lankford (Okla.), Steve Daines (Mt.), Mike Lee (Utah), Ted Cruz (Texas), Ben Sasse (Nebr.), Mike Enzi (Wy.), James Inhofe (Okla.), Tim Scott (S.C.), John Kennedy (La.), Luther Strange (Ala.), Bill Cassidy (La.), Rand Paul (Ky.), Roger Wicker (Miss.), James Risch (Idaho), Dan Sullivan (Ark.), Marco Rubio (Fl.) and Ron Johnson (Wisc.).

Cruz and Rubio were Trump’s last two major Republican primary opponents during the 2016 Republican Presidential primaries.

A retired former Republican Senator previously spoke out against the order.

Alan Simpson, a former GOP whip and United States Senator from Wyoming, wrote in an open letter to Trump that the order would be a “political tinderbox that could explode in the faces of Republicans everywhere, reinforcing negative stereotypes about the party’s dislike of LGBT Americans”.

He wrote: “As one Republican to another, I’d like to offer this bit of advice to President Trump: Don’t do it.”

The retired politician added: “[The order would] reignite a feckless debate that time and time again has forced Republicans to retreat, as we’ve seen with North Carolina’s bathroom bill [and] Indiana’s similar “religious freedom” law. Vice President Mike Pence might consider telling you about the last of these because he spearheaded the effort as governor. It was quite a doozy.”

He continued: “What would you get out of signing this executive order? You would placate a vocal minority that includes some certified hate groups and far-right activists who are truly out of step with most Americans and many Republicans across the country.

“What would the other side get — or in other words, what gifts will you be handing to Democrats and others on a silver platter? A great cause, new supporters, new energy and money, the mother’s milk of politics.

“Aside from being plain cruel and ugly, permitting discrimination against L.G.B.T. Americans in the name of religion would fuel the progressive Democratic base, which devours these morsels of archaic predisposition and then expertly seizes on them — and the big bucks it raises would most likely be used to take you to court.

“I would respectfully suggest that you expend your time and energy on other issues — the solvency of Social Security, the cost of health care, humane immigration reform, building infrastructure and educating kids to succeed — that Republicans could leverage for broad support and for more praise for you and the party as it creeps closer to the midterm elections in 2018.”