President Obama will address the nation's largest gay rights group Saturday, trying to quell an uneasy Democratic constituency.

Obama will speak at a fundraising dinner gala hosted by the Human Rights Campaign, a group that recently blasted the Obama administration for attempting to dismiss the first gay marriage case filed in federal court.

White House spokesman Robert Gibbs said Friday that Obama was working on his speech and would talk about a range of issues.

The dinner falls on the eve of the National Equality March, expected to draw thousands of gay and lesbian activists to the National Mall.

Rep. Barney Frank, the first openly gay member of Congress, called the demonstration "a waste of time at best," saying he'd rather see gay rights supporters lobbying their elected officials than marching in Washington this weekend.

Frank told The Associated Press he considers such demonstrations to be "an emotional release" that does little to pressure Congress.

"The only thing they're going to be putting pressure on is the grass," the Massachusetts Democrat said Friday.

The weekend's events come as a hate crimes bill that would extend federal protection to gay and transgender victims nears passage in Congress.

The House voted Thursday to make it a federal crime to assault people because of their sexual orientation, significantly expanding the U.S. hate crimes law enacted in the days after the 1968 assassination of civil rights leader Martin Luther King Jr.

The Senate is expected to pass the bill, allowing federal prosecutors for the first time to intervene in cases of violence perpetrated against gays.

Gibbs said Obama will praise the bill Saturday.

"The hate crimes protections are long overdue in the president's opinion and believes that their passage represents an important step, and looks forward to, when the legislation gets to his desk, signing it and making that the law of the land," he said.

If that happens, at least one group is considering filing a federal lawsuit, arguing that the bill threatens free speech under broad interpretations and would allow federal intervention into past cases, including ones of alleged rape.

The Liberty Counsel, a law firm that works on religious freedom cases, is directing criticism at the president for his appearance at Saturday's fundraiser, saying it raises questions about propriety when taxpayers must pay the cost for his travel and security.

"The president's speech appears to be a payback for HRC's endorsement of his candidacy," the group said in a written statement, adding the it believes Obama is on the "wrong side of life, morality and liberty.

"Although Obama was recently given the Nobel Peace Prize, he has done nothing to advance peace in this nation or abroad. … Domestically, Obama promotes a culture war. He is not a symbol of peace."

Obama has also been doused with criticism by many gay activists for his slow pace on redeeming campaign promises to end a ban on gays and lesbians from serving openly in the military and pushing tough nondiscrimination policies.

Instead, Obama has taken a slow and incremental approach to the politically charged issues. He has expanded some federal benefits to same-sex partners, but not health benefits or pension guarantees. He has allowed State Department employees to include their same-sex partners in certain embassy programs already available to opposite-sex spouses.

But that remains far short of his campaign rhetoric.

"At its core, this issue is about who we are as Americans," Obama said a 2007 statement on gay issues. "It's about whether this nation is going to live up to its founding promise of equality by treating all its citizens with dignity and respect."

And even before Obama took office, he disappointed gay and lesbian activists who objected to the invitation to evangelist Rev. Rick Warren's participation in the inauguration despite Warren's support for repealing gay marriage in California.

Since taking office, Obama has publicly has committed himself to repealing the "don't ask, don't tell" policy that allows gays and lesbians to serve in the military as long as they don't disclose their sexual orientation or act on it. On Jan. 9, Gibbs answered "yes" when asked whether the administration would end a policy that has seen the dismissal of more than 12,000 troops after their sexual orientation was revealed.

But as president, Obama hasn't taken any concrete steps urging Congress to rescind the Clinton-era policy that some former chairmen of the Joint Chiefs of Staff have acknowledged is flawed.

Yet the office of the current chairman, Adm. Mike Mullen, signed off on a journal article that called for lifting the ban, arguing that the military is forcing thousands of military members to live dishonest lives.

Obama also pledged during the campaign to work for repeal of the Defense of Marriage Act, which limits how state, local and federal bodies can recognize partnerships and determine benefits. But lawyers in his administration defended the law in a court brief. White House aides said they were only doing their jobs to back a law that was already on the books.

The Human Rights Campaign called on the president to repeal DOMA, saying "it is time for you to use your leadership to translate these principles into meaningful action."

House Democrats introduced legislation last month that would overturn DOMA.

The Associated Press contributed to this report.