WASHINGTON — Closing arguments Monday about South Carolina's voter ID law will cap an extraordinary case that already has seen charges of racism directed at the law's author and federal judges' open frustration over state officials' changing stances on implementing it.

Opponents of the embattled law, which U.S. Attorney General Eric Holder blocked last year under the 1965 Voting Rights Act, will challenge the credibility of its chief author, S.C. Rep. Allan Clemmons.

Lawyers for the voter ID law's foes, including civil rights groups, will say Clemmons took false credit for its “reasonable impediment” clause, which allows voters to cast ballots if they have “reasonable” reasons for not having photo identification. Lawyers also will say Clemmons misrepresented his relationship with a man who sent him an email about the law that the Myrtle Beach, S.C., Republican acknowledged under oath last month was racist.

And the attorneys trying to kill the law will argue that S.C. Attorney General Alan Wilson and Marci Andino, executive director of the State Election Commission, lack the legal authority to implement the voter ID law in ways that contradict the law's text or other relevant state laws.

Lawyers for South Carolina will respond that the voter ID law is aimed at preventing election fraud, and they'll point to key Supreme Court rulings that states don't need to show the existence of fraud in order to take steps against it. Attorneys also will argue that state officials' plans for implementing the law aren't contradictory or at variance with its provisions.

At issue under the Voting Rights Act, which protects minorities' access to the ballot box, is whether the South Carolina law's requirement that voters possess one of five forms of photo identification would have a disproportionately harmful impact on African Americans. Of several state voter ID laws under legal scrutiny, the South Carolina case is among the most closely watched because of the state's troubled history of racial relations and because it could have national implications from an expected future U.S. Supreme Court ruling on it. Garrard Beeney, lead attorney for the intervenors, which includes

civil rights groups and individual South Carolinians who claim the law would hurt them, said trial testimony last month showed that minority voters would feel its brunt. They are poorer as a whole and would have more difficulty obtaining the photo IDs, he said. “There really is no dispute from anyone at this trial that blacks are less likely than whites to have the new kinds of ID voters would have to have,“ Beeney told McClatchy on Friday. Chris Bartolomucci, a Washington, D.C., attorney representing the state, disputed that claim.

”The bottom line on (the law's) effect is that it's not going to prevent any lawful voter from voting, whether white or black,“ Bartolomucci told McClatchy.

Since President Barack Obama's 2008 election prompted record turnout by black voters, 34 state legislatures, most with Republican majorities, have taken up bills imposing stricter polling ID requirements, with 16 states passing laws. The laws vary widely, and only some of the states are among the 16 that fall wholly or partly under the Voting Rights Act, which requires the Justice Department to approve all election changes in those covered places. Voter ID laws in South Carolina and Texas are among the most high profile because they are under court challenge, and because of those states' segregationist histories.

A federal court last month rejected the Texas voter ID law, and the U.S. Supreme Court will likely decide its fate, possibly in tandem with the South Carolina law. South Carolina sued Holder over his rejection of its law, which Gov. Nikki Haley signed in May 2011, and the trial last month in Washington featured five days of often dramatic testimony.

Under questioning from the three-judge panel hearing the case, Andino said the state would “give the benefit of the doubt” to voters who lack a driver's license, a military ID or three other new forms of photo ID required by the law. Andino also said notaries would not charge those voters for signing affidavits citing a “reasonable impediment” to obtaining the IDs. And she said the affidavits would not have to be notarized if a notary wasn't available at the polling station where the voter was casting a ballot. Opposing lawyers ripped the notary fees as a new type of poll tax, among the most odious of the former Jim Crow practices used mainly in Southern states to block African Americans from voting. Beeney said the state's more lenient explanations of how it would implement the law contradict its earlier positions and, in part, the law's codified requirements. “The state's constantly shifting interpretation of the (voter ID) act is characterized by multiple inconsistencies, contradictions and non-sequiturs,” Beeney said. “They literally are all over the map.”

The state's most recent pledges that it will abide by Andino's testimony toward the end of the trial last month puts her squarely in the crosshairs. “Ms. Andino's efforts to rewrite the voter law so that it doesn't disenfranchise minorities are certainly admirable, but South Carolina law provides no legal basis for Ms. Andino to interpret the voter ID law, much less provide an authoritative interpretation,” Beeney said.

S.C. Attorney General Wilson expressed confidence that the state will prevail. “This law was passed almost a year-and-a-half ago,” Wilson told McClatchy. “South Carolina looks forward to oral arguments on Monday and to the court's final decision.”

If the three-judge panel upholds the voter ID law in a ruling expected next month, it technically would be in effect in South Carolina for the Nov. 6 elections, but Wilson told the court that such a decision would come too late to apply it. If the judicial panel rejects the voter ID law, a high court ruling would all but certainly come after the elections, so it wouldn't be in place Election Day. In a highly unusual move, the three judges asked South Carolina's lawyers to respond to eight written post-trial questions clarifying how state officials would implement the law. The judges' questions indicated the frustration they'd expressed in skeptical questions at the trial over the state's changing positions.

“Can we then expect that there will not be new facts and new interpretations of (the voter ID law) and its implementation that will be offered during the course of the briefing (Monday) or through Attorney General (Wilson) opinions or any other methods?” the judges asked in one of the post-trial questions. Lawyers for South Carolina provided a succinct response.

“The state does not intend to present any facts or interpretations inconsistent with Ms. Andino's testimony,” they wrote.