Donald Trump's show of support for the LGBTQ community at the 2016 Republican National Convention was nothing more than empty payback for a political favor, according to a new book by his former press secretary Sean Spicer

When Donald Trump promised at the 2016 Republican National Convention to “do everything in my power to protect our LGBTQ citizens,” it was heralded as an unprecedented declaration by a GOP presidential nominee — and a sign of hope that Trump would prove more moderate in his gay-rights policies than his party platform. Two years and multiple anti-LGBTQ policies later, a new book by his former press secretary Sean Spicer reveals that the sentence in Trump’s convention speech was nothing more than empty payback for a political favor.

In The Briefing: Politics, The Press, and The President, out Tuesday, Spicer writes that Trump’s campaign team was on a mission at the time to derail anti-Trump delegates seeking to prevent Trump from becoming the Republican presidential nominee — a process that “Never Trumpers” had initiated by signing a petition ahead of the Republican convention.

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“[Trump campaign chairman Paul] Manafort and his lieutenants went one by one down the list of people who had signed the petition and persuaded them to remove their signatures,” Spicer writes. “How Manafort and company did this was a scene out of 1950s politics — alternating between carrot and stick and sometimes bat, even, at one point, conveniently making the convention’s parliamentarian unavailable to keep the opposition from formally submitting their petition.”

Image zoom Paul Manafort Mark Wilson/Getty

Spicer adds, “The Manafort message was clear: Trump will be our nominee and our next president, and anyone who didn’t want to work to that end could spend the next four years in political Siberia. (No Russia pun intended.)”

The final name that needed to be scrubbed from the petition, Spicer writes, was that of Washington, D.C., delegate Robert Sinners. The book describes an alleged deal between Sinners, who Spicer says told the Manafort team “he wanted Donald Trump to support gay rights,” and senior Trump communications advisor Jason Miller.

“Jason assured Sinners that Trump would be the most ‘inclusive’ candidate the Republican Party ever had,” Spicer writes.

“This is your moment, Robert,” Miller told Sinners, according to the book. “You can deliver this.”

Sinners then reportedly signed “a form that officially removed his name from the petition,” and the deal was done.

“Jason told Sinners Donald Trump’s acceptance speech would acknowledge the LGBT[Q] community, which no other Republican acceptance speech had done,” Spicer writes. “And it did.”

The White House and Sinners did not immediately respond to PEOPLE’s requests for comment.

Image zoom Donald Trump Chip Somodevilla/Getty Images

During Trump’s acceptance speech at the Republican National Convention in July 2016, he referenced the then-recent mass shooting at a gay nightclub in Orlando, Florida, which resulted in 49 deaths.

“As your president, I will do everything in my power to protect our LGBTQ citizens from the violence and oppression of a hateful foreign ideology,” Trump said, according to The Hill, referencing the fact that the shooter, Omar Mateen, had pledged allegiance to ISIS.

RELATED VIDEO: Sean Spicer’s Greatest Hits

The crowd cheered, and Trump said, “As a Republican, I’m so happy to hear you cheering for what I just said.”

Image zoom Regnery Publishing

But since his inauguration, Trump has come under fire by LGBTQ rights groups for ordering the Department of Defense to stop accepting transgender people in the military, and for twice failing to acknowledge pride month, among other controversial incidents. Trump’s administration also sided last year with a Colorado baker who refused to bake a wedding cake for a same-sex couple in a high-profile Supreme Court case. And Trump’s attorney general, Jeff Sessions, last year reversed course on an Obama-era policy protecting transgender people from workplace discrimination.

In October 2017, shortly after that reversal, ACLU legislative director Ian Thompson called Trump’s administration “easily the most anti-LGBT administration in at least a generation,” The Hill reported at the time. “They are hard at work trying to dismantle and erase every gain LGBT people have made since 2009.”

In his book, Spicer presents his perspective on some of the most controversial moments in the White House and seems to assert his enduring loyalty to Trump.