Four years ago, Barack Obama captured 96 percent of the black vote. But this year, in an election in which every vote may matter, Mitt Romney is not giving up on that front.

On Wednesday, Romney will make a pitch to the nation's premier civil-rights group, testing Obama's overwhelming support among black voters by trying to pry away defectors with his pro-jobs message at a time of 14.4 percent unemployment among African Americans.

Obama is passing up the chance to address the group, the National Association for the Advancement of Colored People, and sending Vice President Joseph Biden instead.

While blacks are expected to solidly back Obama again this year, he faces challenges in generating the same enthusiasm as in 2008. The level of black turnout could be especially crucial in states like North Carolina and Virginia, where black voters had an outsize influence in the president's relatively narrow victories four years ago.

"In 2008, he won North Carolina by about 14,000 votes," said Bill Randall, a black Republican who lost a recent primary for a congressional seat in the state. But "support is waning," he said, adding that the president's "policies are not doing things that are going to spur economic growth."

Other black leaders said Romney would need more than an economic message to improve on Sen. John McCain's dismal level of black support in 2008 and return to the 11 percent that George W. Bush won in 2004.

"Romney could do much better than John McCain," said Benjamin Todd Jealous, the president of the NAACP, the 103-year-old group Romney plans to address Wednesday at its annual convention in Houston.

Jealous said people had heard Romney's message on jobs and the economy and, "It is not resonating with our base," in part because talk of deregulation brings to mind Wall Street bailouts and how General Motors might have gone bankrupt if Romney had been in the White House.

"If he's going to pick up more support in the black community," Jealous said, "he has to send a message that he's prepared to lead on issues that we care about."

Topping the list is a wave of voter-identification laws that Democrats say will suppress minority participation in November.

"We are living through the greatest wave of legislative assaults on voting rights in more than a century," Jealous said Monday in his opening speech at the convention. "In the past year, more states have passed more laws pushing more voters out of the ballot box than at any time since the rise of Jim Crow."

Nearly a dozen states have passed strict voter ID laws in the last two years largely with the support of Republican lawmakers, who say that they are needed to prevent fraud. Democrats argue that the laws are really meant to suppress turnout by poor and minority voters, who tend to vote Democratic and who disproportionately lack government-issued identification.

The issue caused a stir recently when a top Republican official in Pennsylvania said the state's new voter ID law would allow Romney to carry the state.

Texas, as it happens, is one of the states with a tough new law, which is the subject of a federal court hearing in Washington this week as the NAACP meets in Houston. The Justice Department has found that the law will "disenfranchise at least 600,000 voters," many of them members of minority groups. The state is challenging the ruling and a key provision of the Voting Rights Act of 1965.

In remarks to the NAACP Tuesday, Attorney General Eric Holder said the Texas law would be harmful to minority voters.

Holder said that under the law, "many of those without IDs would have to travel great distances to get them — and some would struggle to pay for the documents they might need to obtain them."

Romney has rarely weighed in on voter ID laws during the campaign. A spokeswoman for the campaign, Andrea Saul, summarized his position in an email: "Governor Romney believes that every legal vote should count."

Although the Romney campaign recently named an adviser to help frame its message to black voters and in May the candidate visited a charter school in a poor black neighborhood of West Philadelphia, most of his courtship of minorities has been focused on Hispanics, who could play a crucial role in swing states like Colorado, Florida and Nevada.

Surveys show that blacks still overwhelmingly support the president. In the latest Gallup weekly tracking poll, 87 percent approved of the job Obama is doing. But Jealous said that it would be difficult for the president to inspire the same turnout among blacks as in 2008: The historic import of his candidacy for blacks has passed, and people are still struggling in a stalled economy.

It might appear that Obama is taking black voters for granted by skipping the NAACP event, which he attended four years ago. Jealous said the president had signaled as recently as a week ago that he would speak to the group, but his office said he had a scheduling conflict. Biden, who also enjoys strong support among blacks, will speak Thursday.

Obama is focused this week on countering a disappointing jobs report released last Friday — proposing on Monday to extend a middle-class tax cut, a message he planned to repeat Tuesday at grass-roots events in Iowa.

Although a battleground state for November, Iowa has few black voters compared with other swing states where blacks turned out in large numbers for Obama in 2008, including Florida, Ohio and Pennsylvania.

One factor in the president's favor may be that as a result of his success and that of other black politicians, the size of the minority electorate has grown, said Katherine Tate, a political scientist at the University of California, Irvine.

"Black voters are regularly participating in politics nowadays because of their elected numbers in government," she said. "An African-American member of Congress once said that because of Obama his mother now watches cable news regularly and talks to him regularly and heatedly about policy matters."