LOS ANGELES - President Obama claimed the mantle of champion for the LGBT community on Wednesday night, telling a group of 600 gay and lesbian donors at a star-studded fundraiser that he "could not be prouder" of his administration's work to advance fairness and equality.

From the effort to lift an HIV/AIDS travel ban, to passage of a hate crimes law and repeal of "don't ask don't tell," Obama credited his friends and family, staff and military service members as the inspiration behind his advocacy for gay rights in the White House.

"It's something that I'm personally very proud of," he said of the accomplishments.

One of those sources of inspiration introduced Obama - Dr. Vito Imbasciani, a urological surgeon and colonel in the U.S. Army National Guard who served three tours in Iraq and Afghanistan. Imabasciani, who is gay, explained that it was his commander-in-chief who allowed him to finally "be himself" after serving for 26 years.

"Until last year, the price of my service was to live a lie," the soft-spoken Imbasciani said. "But not anymore."

"Thanks to the unyielding efforts of President Obama I can serve my country openly with my family by my side," he added, referring to the repeal of "don't ask don't tell." Imbasciani said he and his partner have two adopted children of Mexican descent.

Invoking "Vito's story," President Obama said that his administration's record of progress for gays and lesbians over the past three years is "just one more step" in a broader movement for greater equality for all Americans.

"It's part of our history of trying to make this union a little bit more perfect," Obama said. "In successive ways, the history, the scope of this country has always been to further broaden the meaning of citizenship, to include more and more people. To give better and better expression to our highest aspirations, to make the country more fair, and more just and more equal."

While the president did not specifically address his rival Mitt Romney's record on gay rights, he did suggest the former Republican governor would be much less supportive.

"[There is a] fundamentally different vision about what's going on," Obama said of his opponent's campaign. "And a lot of this debate's going to be about the economy, but also obviously there's a different vision about how we create an inclusive America.

"I refuse to let anybody re-impose a law that would force Vito back into the shadows when he's serving on our behalf and our safety and our security," Obama said to resounding applause. "That's not something I will tolerate."

Romney, it should be noted, has not publicly called for re-imposing a ban on gays serving openly in the military. During a November 2011 primary debate, Romney suggested that he would allow the repeal to stand, saying "That's already occurred and I'm not planning on reversing that at this stage."

Gay and lesbian supporters have been some of Obama's most active and generous supporters, with many doubly energized when the president announced newfound support for same-sex marriage in an interview with ABC News last month.

The LGBT Leadership Council Gala at the Regent Beverly Wilshire tonight and a subsequent fundraiser at the home of "Glee" creator Ryan Murphy and his partner David Miller were expected to raise north of $2.5 million combined for the Obama Victory Fund, according to figures provided by the Obama campaign.

Comedian Ellen DeGeneres and "Glee" star Darren Criss entertained the crowd at the Wilshire before Obama took the stage. While the president spoke, many same-sex couples in the crowd had their arms around each other while others snapped photos with iPhones and cameras.

"This is going to be a very close election," Obama said. "Not because people buy what they're selling, but just because a lot of folks have given up feeling that anything is going to make their lives better.

"But when folks come together and say it's time for a change, change happens," he said.