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 how they would enact the law.

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, a Myrtle Beach Republican.

Lawyers for groups opposed to the voter ID law, 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.

Those lawyers also will say Clemmons misrepresented his relationship with a man who sent him an email about the law that the Myrtle Beach Republican acknowledged under oath last month was racist. Clemmons responded to that email, “Amen, ... thank you for your support.”

The attorneys trying to kill the law also will argue 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 the voter ID law is aimed at preventing election fraud, and they will point to key Supreme Court rulings that states don’t need to show the existence of fraud in order to take steps against it. Those attorneys also will argue the plans of state officials to enact the law aren’t contradictory or at variance with its provisions.

At issue under the Voting Rights Act, which protects minority access to the ballot box, is whether the S.C. 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 S.C. case is among the most closely watched because of the state’s troubled history of race relations.

The case also could have national implications because of an expected future U.S. Supreme Court ruling on it.

Garrard Beeney, lead attorney for the civil rights groups and individual South Carolinians who claim the law would hurt them, said trial testimony last month showed 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 said 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 said.

Supreme Court to decide issue?

President Barack Obama’s 2008 election prompted record turnout by black voters.

Since then, 34 state legislatures, most with Republican majorities, have taken up bills imposing stricter voter ID requirements, with 16 states passing laws. 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 states with histories of discriminating against minorities.

The voter ID laws in South Carolina and Texas, both covered by the Voting Rights Act, are among the most high profile because they are under court challenge.

A federal court last month rejected the Texas voter ID law. The U.S. Supreme Court likely will decide its fate, possibly in tandem with the S.C. law.

South Carolina sued Holder over his rejection of its law, which Gov. Nikki Haley signed in May 2011.

Under questioning from the three-judge panel hearing the case last month, 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 laws used in Southern states to block African-Americans from voting.

Beeney said the state’s more lenient explanations of how it would enact the law contradict its earlier positions and, in part, the law’s codified requirements.

If the three-judge panel upholds the 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 the law then. If the panel rejects the voter ID law, a Supreme Court ruling would all but certainly come after the elections, so it wouldn’t be in place on Election Day.