Tom Perez, the assistant attorney general in charge of the department's Civil Rights Division, said pending legislation in Congress will allow the department to attack discrimination against lesbian, gays, bisexuals and transgender people, a group often referred to by the acronym LGBT.
That would be new territory for the division that has historically gone after discrimination based on race, gender or religion. It would also be a major shift from the division's work during the Bush administration, which opposed expansion of the federal hate crimes law to prosecute those who attack gays.
Perez on Wednesday he gave his first speech to division employees, saying the division must be transformed "so that we are capable of tackling the civil rights challenges of the 21st century," include issues not historically addressed by the department.
"We must fight for fairness and basic equality for our LGBT brothers and sisters who so frequently are being left in the shadows," he said, and to "ensure that there's a level playing field in which our LGBT brothers and sisters are judged by the content of their character."
Allison Herwitt, legislative director for Human Rights Campaign, the nation's largest gay rights group, called Perez's words "fantastic."
"What's so different between this administration and the last is that we have people who want to have these protections in place and to enforce these protections, and you have the top of the Civil Rights Division willing to openly talk about these protections," said Herwitt.
Conservative activists argued that such moves could come at the expense of people of religious faith.
"Too often it's religious liberty that's at stake when homosexuality is promoted in our society. The rights of people of faith who adhere to a biblical view of sexuality should not be crushed under the Obama administration's political promises to homosexual activists," said Carrie Gordon Earll, senior director of Focus on the Family Action.
Federal civil rights laws say little about attacks or discrimination fueled by anti-gay bias. The Senate, though, is on the verge of passing legislation that would broaden the hate crimes law and allow federal prosecutions of bias attacks on gays.
Attorney General Eric Holder has repeatedly urged Congress to pass the new hate crimes law, saying the expansion of federal prosecutions for such attacks is long overdue.
Separately, the House has taken a tentative step to consider a law that would outlaw anti-gay or gender identity discrimination in the workplace.
During the Clinton administration, the department's Civil Rights Division had an internal group that examined gay rights issues, but the effort ended during the Bush administration.
Perez's goal of greater government action on gay rights speech can only come if Congress changes civil rights law.
That seems likely in the case of bias-driven violence. The new hate crimes bill has survived a number of votes and now needs only a final vote in the Senate before going to the president's desk for his signature. In the case of the workplace bill, called the Employment Non-Discrimination Act, the chances of success are less clear.
Twenty-one states already have laws prohibiting workplace discrimination on the basis of sexual orientation, and 12 extend those laws to gender identity - California, Colorado, Iowa, Illinois, Maine, Minnesota, New Jersey, New Mexico, Oregon, Rhode Island, Vermont and Washington. Several other states protect public employees who are gay or transgender.