Republicans invited the veterans before the Senate Judiciary Committee to condemn Kagan's decision as dean of the Harvard law school to limit military recruiting -- a move that has become a focus of Republican attacks.
Kagan prevented the recruiters from using Harvard's career office under university anti-discrimination rules because of the "don't ask, don't tell" policy that blocks gays from openly serving in the military.
"How did we reach the point in this country where we're nominating someone who unapologetically impeded the military?" asked Army National Guard Captain Pete Hegseth, executive director of Vets for Freedom.
Retired Army Captain Flagg Youngblood said Kagan's policy amounted to a "separate but equal" approach to the military, comparing it to racial segregation.
"Dean Kagan's unlawful brand of segregation clearly estranged the students of Harvard Law School from the military," he said.
The Republican-orchestrated charges came as the committee wrapped up hearings on Kagan's nomination with testimony from 24 critics and supporters. Kagan did not attend the session.
During her testimony earlier this week, Kagan defended her Harvard actions and said she allowed military recruiters access to the law school through student groups. Recruiting numbers actually went up during that period, she said.
Captain Kurt White, a West Point graduate and Iraq veteran who attended Harvard law school while Kagan was dean, was called by Democrats to dispute the characterization of her as anti-military.
White said Kagan went to great lengths to show appreciation for veterans, singling them out for introductions on the first day of school and inviting them to a Veteran's Day dinner.
"She made each of us feel she was the one who was honored," White said, adding he wanted to testify to "dispel the untrue and unfair accusations of anti-military bias" against her.
Kagan, 50, appears headed toward easy confirmation when the Senate returns from a week-long July 4 break. She calmly sailed through three days of hearings that drew praise even from some of her Republican critics.
Kagan would replace retiring Justice John Paul Stevens on the ideologically divided court. She would become the second successful female appointment to the court by President Barack Obama after last year's confirmation of Sonia Sotomayor.
Her nomination has not sparked a political fight like many past nominees. During the hearing, Republicans questioned her lack of experience as a judge and accused her of being a liberal political activist who would be a rubber-stamp for Obama's agenda.
But Kagan calmly rebutted each charge during more than 16 hours of testimony and senators in both parties predicted her confirmation.
Republican Senator Orrin Hatch told witnesses he was wrestling with his decision on whether to vote to confirm Kagan.
"You can't help but like Elena Kagan," Hatch said, adding he was worried that she might not live up to everything she promised during the hearings.
"I'm anguishing over this," he said.
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