President Barack Obama's choice to lead the Pentagon, former GOP Sen. Chuck Hagel, will likely be confirmed next week, one of his most dogged opponents said Sunday.

"I'm confident that Sen. Hagel will probably have the votes necessary to be confirmed as secretary of defense," Sen. John McCain, R-Ariz., said Sunday on NBC's "Meet the Press."

After Senate Republicans voted to sustain a filibuster and block the former Nebraska senator's nomination from advancing toward confirmation, McCain acknowledged that Hagel will likely win confirmation once the chamber returns from its recess.

"I think it's a reasonable amount of time to have questions answered," McCain said of the week-and-a-half-long window which Senate Republicans demanded to pore more thoroughly over their former colleague's records.

Democrats and the Obama administration have complained that a filibuster for a defense secretary nominee is without precedent. Moreover, they argue that filling the defense post is particularly urgent given outgoing Secretary Leon Panetta's plans to leave the Pentagon, and the looming "sequester" of automatic spending cuts, which fall heavily upon the defense budget.

The administration publicly shrugged off, though, the notion that the delay had damaged Hagel's ability to serve effectively.

"No, he's not going to be a weaker defense secretary," said Denis McDonough, the president's new chief of staff, "he's going to be a great defense secretary."

Wrapped up into the GOP's objections are the desire to ding the administration, a demand for fuller answers to the Sept. 11, 2012 attacks on the diplomatic post in Benghazi, Libya, and personal quarrels with Hagel over his criticism of President George W. Bush and the handling of the war in Iraq. McCain denied, though, that Republicans' attacks on Hagel were personal in nature.

"99 percent of it has to do with the positions Sen. Hagel has taken," he said.

The Hagel fight has consumed Congress in recent weeks, threatening to expend Obama's political capital as he enters a second term. It's yet to be seen whether this fight, and the looming fight to replace the sequester with other equivalent savings, would affect other elements of the Obama agenda — including gun control, and immigration.

Amid a New York Times report that suggested the White House had pushed ahead with its own immigration bill, McDonough said it was consistent with Obama's promise to simply be prepared with his own alternative plan. Obama, McDonough said, was still hoping that a bipartisan Senate group would be able to produce its own comprehensive immigration reform proposal.

"I believe we're making progress on a bipartisan basis," said McCain, a member of the eight-member, bipartisan Senate group working on the immigration proposal. The Arizona senator said, though, that Obama had had no communications with the Senate group.

"Does the president really want a result?" asked McCain, reflecting Republicans' concerns on the politics of immigration. "Or does he want another cudgel so he can beat up Republicans to get an advantage in the next election?"