Attorney General Eric Holder on Tuesday compared the new Texas voter ID law to the post-slavery efforts to keep blacks from voting known as a "poll taxes."

The law was passed last year by the GOP-led state legislature, then signed by Gov. Rick Perry, in an effort to curb voter fraud.

In a speech at the annual NAACP conference, in Houston, Holder said many voters would have to travel "great distances" to get a government-issued photo ID and that some would "struggle" to pay for the requisite paperwork.

"We call these poll taxes," Holder said.

He also said the Texas law hurts minorities and that politics is the driving force behind the issue.

Holder called Texas the "center of our national debate" on voting rights issues and vowed the Justice Department would "aggressively" fight to enforce those rights.

He delivered the remarks on the second day of a federal trial in Washington, D.C., regarding the law, which requires voters to show photo IDs at polling places.