By David Ingram and Aruna Viswanatha
WASHINGTON (Reuters) - The Justice Department sued North Carolina on Monday in a bid to block a new state law that forces voters to present a photo identification before casting a ballot and limits early voting, arguing the measure discriminates against minorities.
The suit marked the second time in recent months that the Democratic Obama administration has challenged a voting law enacted by a Republican-led state. In August, it sued to block a 2011 Texas voter-identification measure.
Attorney General Eric Holder said the North Carolina law imposes several "troubling new restrictions" on voters including reducing early voting days, eliminating same-day registration during the early-voting period and imposing a restrictive photo-identification requirement for in-person voting.
"The Justice Department expects to show that the clear and intended effects of these changes would contract the electorate and result in unequal access to the participation in the political process on account of race," Holder, joined by federal prosecutors based in North Carolina, said during a news conference announcing the lawsuit.
The North Carolina law is one of a series enacted in Republican-governed states imposing new requirements on casting ballots. Republicans argue that the changes are needed to combat voter fraud. Democrats assert that the laws are intended to make it harder for blacks and other voters who are likely to vote for Democratic candidates to cast their ballots.
Holder said his department could bring more voting rights cases. "I fear that it will not be our last," he added.
The department's suits against Texas and North Carolina followed a June U.S. Supreme Court ruling in an Alabama case that invalidated part of the 1965 U.S. Voting Rights Act that the federal government had previously relied upon in challenging state voting laws.
Republican Governor Pat McCrory signed North Carolina's sweeping voting changes into law in August, saying at the time: "Common practices like boarding an airplane and purchasing Sudafed (a common decongestant) require photo ID, and we should expect nothing less for the protection of our right to vote."
In a statement on Monday, McCrory called the Justice Department's lawsuit an overreach with no merit. "I believe that North Carolina is in the mainstream on this issue, and it's the Justice Department that's working in the fringes," he added.
Civil rights groups filed suit against the law immediately after it was signed, and Democratic U.S. Senator Kay Hagan of North Carolina asked Holder to review the matter.
Holder said that by restricting access to the polls and the ease of voter participation, the law would shrink rather than expand people's ability to cast ballots. He said he was especially troubled that the law would significantly narrow the early voting period that enabled hundreds of thousands of voters, including a disproportionately large number of minority voters, to vote during the most recent election cycle.
U.S. elections generally are held on Tuesdays, but North Carolina and some other states allow voters to cast ballots early in part to make it more convenient to vote.
More than 70 percent of blacks who voted in the November 2008 and 2012 elections in North Carolina did so in this early period, according to the Justice Department.
The department's suit asks the court to block four provisions of the North Carolina law:
* The elimination of seven days of early voting prior to Election Day - cutting it from 17 to 10 days while leaving the overall number of early voting hours unchanged;
* the elimination of same-day voter registration during early voting;
* the prohibition on counting certain provisional ballots, which a voter fills out when there are questions about his or her registration;
* and the adoption of an ID requirement that is stricter than the Justice Department allows.
Changes in voting laws can affect voter turnout and swing close elections. For civil rights advocates, recent changes echo the earlier, century-long fight to win voting rights for black Americans in the U.S. South.
The Justice Department has struggled to respond to state laws it believes are civil rights violations without relying on the parts of the U.S. voting law invalidated by the high court.
The challenge to North Carolina would fall under the Voting Rights Act's Section 2, which prohibits state voting practices or procedures that discriminate by race. Under that section, the federal government will have to prove that discrimination was both the intent behind the North Carolina law and its effect.
Requirements for voters to show identification have been a flashpoint. The Justice Department has approved of them in some states such as Virginia that take steps to ensure that IDs are available at little to no cost, but not in states where it said the mandate would be a burden on the poor and minorities.
In its North Carolina suit, the department said that even though blacks comprised 23 percent of the state's registered voters, they accounted for 34 percent of registered voters who did not have a driver's license or other ID provided by the state's motor vehicles department.
The case was assigned to a federal judge in Winston-Salem, North Carolina.
(Additional reporting by Colleen Jenkins in Winston-Salem, N.C., Editing by Howard Goller and Will Dunham)