Tomorrow Attorney General Eric Holder will gave a major speech on voting rights at the LBJ presidential library in Austin. According to the library, “Holder will discuss the importance of ensuring equal access to the ballot box and strengthening America’s long tradition of expanding the franchise.”

Holder’s speech could not come at a more critical time. Over the last year we’ve witnessed an unprecedented GOP war on voting, with a dozen Republican governors and state legislators passing laws to restrict voter registration drives, require birth certificates to register to vote, curtail early voting, mandate government-issued photo IDs to cast a ballot and disenfranchise ex-felons who’ve served their time. The Brennan Center for Justice has estimated that “these new laws could make it significantly harder for more than 5 million eligible voters to cast ballots in 2012,” and notes that “these new restrictions fall most heavily on young, minority and low-income voters, as well as on voters with disabilities.”

On Saturday, in conjunction with UN Human Rights Day, thousands of activists and concerned citizens in New York City held a march and rally to protest these restrictive new laws. The march began outside the New York headquarters of the Koch brothers, who have given more than $1 million to the American Legislative Exchange Council (ALEC), the shadowy conservative advocacy group that has masterminded the push for new voter ID requirements this year. Protesters held signs that read “Koch Bros & The 1%: Undermining Democracy.”

The march then continued to the UN for a rally with civil rights leaders, good-government activists and voting rights experts. One organizer told me that 20,000–25,000 people participated in the march, which, if true, would be a very good turnout on a chilly December morning. (The AP, on the other hand, said that “hundreds” protested, though the numbers seemed significantly larger to me). Groups sponsoring the march/rally included the NAACP, SEIU1199 and the United Federation of Teachers.

The purpose of the march was both practical and symbolic. “The march on Saturday was an indication that Americans will not go backwards,” said Judith Browne-Dianis, co-director of the Advancement Project. “We will keep up the momentum to end voter suppression by taking to the streets, to the legislatures and to the courts. We won’t be silenced by those who want to undermine democracy.”

The Advancement Project has helped gather 120,000 signatures asking the Justice Department “to oppose any discriminatory laws that will disenfranchise voters.” The Justice Department has that authority under the Voting Rights Act. DOJ has sent pointed questions to states like Texas and South Carolina about their new laws, but we still don’t know how aggressively they will enforce the existing laws on the books. Perhaps Holder’s speech tomorrow will shed some light.

Occupy A Voting Booth,” read one sign I spotted on Saturday. Many of the speakers echoed that theme. While Occupy Wall Street is rightly fighting for systemic change in a broken political system, the demonstrators on Saturday are leading a struggle to protect the most basic of political rights—the right to vote. Because of the new GOP laws, Bob Fertik of recently told me, voting itself has become an act of resistance.