The Senate passed groundbreaking legislation Thursday that would make it a federal crime to assault an individual because of his or her sexual orientation or gender identity.

The expanded federal hate crimes law now goes to President Obama's desk. Obama has pledged to sign the measure, which was added to a $680 billion defense authorization bill.

Several religious groups have expressed concern that a hate-crimes law could be used to criminalize conservative speech relating to subjects such as abortion or homosexuality.

Attorney General Eric Holder has asserted that any federal hate-crimes law would be used only to prosecute violent acts based on bias, as opposed to the prosecution of speech based on controversial racial or religious beliefs.

Holder called Thursday's 68-29 Senate vote to approve the defense spending bill that included the hate crimes measure "a milestone in helping protect Americans from the most heinous bias-motivated violence."