"Ask yourself, who is really the friend of women and the LGBT community? Donald Trump with actions or Hillary Clinton with her words?" he said at a New Hampshire campaign event shortly after the June 2016 attack at the gay nightclub in Orlando. "I will tell you who the better friend is. And some day I believe that will be proven out big league."
But while Trump's White House has been silent on the march and -- unlike every year since 2009 -- has not announced it will host a reception recognizing June as LGBT Pride Month, the departments of Defense and State are observing the month this year; and Ivanka Trump, a White House adviser to her father, took to Twitter to wish "everyone a joyful #Pride2017."
Conservative gay Americans, for their part, view the march as a partisan event emphasizing "division far more than equality," said Gregory T. Angelo, president of Log Cabin Republicans, a conservative LGBT group.
"For months now we've heard that Trump is going to 'roll back' advances made by the LGBT community, and time and again those rumors were proven to be unfounded," he told CNN. "All of this chicken-littling has turned the self-styled 'Resistance' into little more than a hollow cliche."
Gay rights activists, however, say Trump's refusal to issue an official White House statement commemorating LGBT Pride Month -- chosen by advocates to commemorate New York's Stonewall uprising in 1969 -- is symptomatic of the White House's agenda for LGBT Americans. The march on Sunday will be an attempt to the let the Trump administration know that America's LGBT community will not be ignored, they say.
"The reason we're all marching on the 11th is because it's our job to stay visible and to stay louder than ever," Sarah Kate Ellis, president and CEO of GLAAD, a nonprofit that monitors the media's portrayal of LGBT people. "Our visibility has been our greatest strength."
"Pride over the past few years has become more celebratory than ever," Ellis added. "But I think we're back to the times where it's important for us to be loud and resistant and fight for our rights and visibility. I want them to take the message that we're not going away, that we will not be erased and that we need to be acknowledged and brought into the conversations and into legislation."
Lawmakers, including House Minority Leader Nancy Pelosi and fellow California Democrats Adam Schiff, Ted Lieu, and Maxine Waters, are scheduled to address activists Sunday at the various marches and challenge them on how they can better respond in the current political climate.
Outside the Beltway, meanwhile, legal teams and organizations that once fought for same-sex marriage in courthouses across the country have been training their sites on a new purpose — so-called religious freedom bills at the state level that would allow individuals and businesses to deny services they feel are contrary to their religious beliefs.
While defenders of the bills say they protect First Amendment rights, LGBT groups say they merely legalize discrimination.
Vice President Mike Pence signed the country's first state religious freedom bill into law in Indiana during his governorship in 2015.
Evan Wolfson, who founded Freedom to Marry, an organization often credited for same-sex marriage victories on state and federal levels, said the legislation stems from the same "anti-gay industry" as in the past, adding that the political and legal landscapes have changed since the Supreme Court guaranteed same-sex marriage equality in 2015.
"There's no question there's a lot of things to be afraid of," he said. "[But] the battle lines are not where they were before and we have more to work with in those battles."
LGBT civil rights groups are also fighting so-called "bathroom bills," like North Carolina's now repealed law that targeted transgender people's use of public restrooms.
"This is an attempt by an extreme group of politicians to target a community for political purposes -- efforts to legislate transgender people out of life," said Sarah McBride, national press secretary for the Human Rights Campaign, which notes transgender people face high rates of job discrimination, homelessness and physical violence and are more likely than even non-transgender sexual minorities to experience violence from the police.