Marchers make their way down Pennsylvania avenue as the second official anniversary commemoration of the March on Washington gets underway, Aug. 28, 2013, in Washington. Credit: Bill O'Leary/The Washington Post/Getty Images

Republican Party officials reached out to organizers of this week's March on Washington commemoration with a series of suggestions for possible GOP speakers, but several of the people they recommended were never contacted with invitations to speak, according to Republican National Committee officials.

Miscommunication and lack of coordination appear to have played a role in at least some of the invites not going out to Republican office-holders. Event organizers say they assumed Sen. Tim Scott, R-S.C., couldn't attend, based on a failure to RSVP to an earlier, more general invitation. But his office says he was never actually invited to speak, and he may have been able to attend if he was formally invited.

More than half a dozen different prominent Republicans were invited to speak, but several of the invitations went out quite late in the planning. All sent their regrets.

Regardless of the motivations, the result was that an ostensibly non-partisan program on the steps of the Lincoln Memorial took on a political edge. Heated comments on affirmative action, gun rights, and racial discrimination in law enforcement echoed from the podium, with none of the 30-plus speakers - a list that included all three living Democratic presidents - representing a Republican point of view.

That's not a tone that members of the King family and other groups involved in organizing the day wanted. And Republican Party officials, intent on reaching out to minority voters and with a large television audience tuning in to the 50 th anniversary events, say they didn't want the GOP to go unrepresented, either.

After it became clear that big-name Republicans like the Bushes were not going to be able to attend, RNC officials offered help in finding one or more appropriate Republican speakers, according to Sean Spicer, the RNC's communications director.

"We were very proud of our efforts to commemorate this historic event, which we did in several ways over the last few days," Spicer said. "Furthermore, we offered up assistance to the organizers of the event - our assistance in facilitating any Republican speakers that they would be interested in having."

Starting August 14 - two weeks before the commemoration - GOP officials offered help in reaching out to a range of other Republicans. That list, according to an RNC official, included Scott, who is the only African-American currently in the Senate; former Rep. J.C. Watts, R-Okla., who is black; and T.W. Shannon, the 35-year-old African-American speaker of the Oklahoma House of Representatives.

Organizers did invite several prominent Republicans - including both Presidents Bush, former Gov. Jeb Bush, former Gov. Mike Huckabee, House Speaker John Boehner, House Majority Leader Eric Cantor, and Sen. John McCain - to speak. They also reached out late in the planning process to the office of Rep. James Sensenbrenner, a veteran congressman from Wisconsin who has been prominent on voting-rights and sentencing-reform issues.

All of those invited declined, however, with the two former presidents citing health concerns, and the others pointing to scheduling conflicts. Cantor was invited just 12 days before the event, and Huckabee told ABC News he was invited just last week - too late for him to juggle other commitments.

"I was invited and so wished I had been able to do it," Huckabee said in an e-mail to ABC. "I didn't receive the invitation until last week, however, and it was too late for me to re-arrange things."

One Republican aide likened the late flurry of invites to "unvitations," the "Seinfeld"-inspired practice of inviting someone to an event with the knowledge that they won't attend.

That accusation doesn't sit well with those who put the event together. The lack of Republicans was a disappointment to event organizers, up to and including members of the King family, said Donna Brazile, a veteran Democratic strategist who was tasked by event organizers with helping line up a Republican for the program.

She said it's just wrong to suggest that organizers didn't want Republican voices represented.

"It's not the fault of the King Center. The attempt was made, from the [former] presidents to the speaker of the House, to various other leaders," she said.

Brazile said she assumed Scott was invited to speak. Other organizers said that when he didn't respond to an invitation sent to all members of Congress months ago - to attend, though not necessarily to speak - that he was assumed to be unable to attend.

A Scott aide said it's impossible to say whether he would have attended if offered a speaking slot. But the aide pointed out that Scott wrote an op-ed about the anniversary this week and spoke at a church in Charleston about King's legacy Wednesday night.

"The senator believes the anniversary was a day to remember the extraordinary accomplishments and sacrifices of Dr. King, Congressman John Lewis, and an entire generation of black leaders," said Greg Blair, a Scott spokesman.

Without addressing specific names, Brazile said organizers weren't going to put a Republican into the program who didn't have the stature to speak alongside presidents and heroes of the civil-rights movement. She said she worked directly with GOP leadership offices on Capitol Hill to find an appropriate speaker, to no avail.

"They weren't looking for any Republican out of the wilderness," Brazile said. "For Republicans to try to make an issue out of this - that's a sign of desperation. The overtures were made."

In a statement, the event's executive producer, the Rev. Leah Daughtry, cited "scheduling conflicts" for the inability to include Republican voices.

"We regret that scheduling conflicts precluded the participation of many of our invitees, but we are confident that whether they were in Washington, DC or in their hometowns, everyone joined the celebration of Dr. King's dream and remains committed to working and fighting for the fulfillment of the ideals Dr. King articulated 50 years ago," Daughtry said.

In the event's aftermath, though, some Republicans are suggesting their party was intentionally excluded, while some Democrats have accused Republicans of ignoring the King legacy.

"They asked a long list of Republicans to come," Julian Bond, a veteran civil-rights activist who spoke at the event, said on MSNBC Wednesday. "To a man and woman they said 'no.' And that they would turn their backs on this event was telling of them, and the fact that they seem to want to get black votes - they're not going to get 'em this way."

"I would have liked to have seen Republican speakers at that," NAACP's Ben Jealous said during an appearance at the National Press Club. "There are messages that could have been brought."

But the RNC's Spicer said it should have occurred to organizers to make a special effort to invite Scott, given the fact that he's the only African-American U.S. senator.

"Overlooking Tim Scott would be like overlooking the president for the State of the Union speech," he said.

And looking at a speakers' lineup that included lower-profile Democrats such as Rep. Marcia Fudge, D-Ohio, and Rep. Donna Edwards, D-Md., there were plenty of other "nationally known" black Republicans who could have been included, he said.

UPDATE: As Roll Call first reported, Sen. Scott's office did respond to the request to attend the event by noting that he would be in South Carolina that day and would be "unable to attend."

On August 9, a Scott aide replied to what appears to have been a form e-mail invitation sent to all members of Congress: "Thank you for extending to Senator Tim Scott the invitation to the 50th Anniversary of the March on Washington on August 28th. Unfortunately, the Senator will be in South Carolina during this time, so he will be unable to attend the event. Please do, however, keep him in mind for future events you may be hosting."

That RSVP, however, does not mean that Scott might not have tried to rearrange his schedule if he was invited as part of the speaking program, according to Scott's office. Scott's office and organizers confirm that no additional contacts were made with Scott's office to extend an invitation to speak.