Washington ( CNN ) -- During his 2000 presidential run , a New Hampshire voter asked Republican Sen. John McCain who he might choose as secretary of defense . McCain responded by tossing out the name of a dear old friend and colleague , the very man who would be nominated to that post by a Democrat and frequent McCain target 13 years later . `` There 's a lot of people that could do that , '' he told voters at a January town hall in Nashua , New Hampshire . `` One of 'em , I think , is Sen. Chuck Hagel . '' Now Hagel has been nominated for that same job , by McCain 's 2008 campaign rival , President Barack Obama . But when the Senate Armed Services Committee meets on Thursday to discuss the nomination , McCain will be one of Hagel 's biggest skeptics . What Hagel will say Thursday . `` My biggest concern is his overall attitude about the United States , our role in the world -- particularly in the Middle East and whether we should reduce the Pentagon further -- but mainly his general overall world view , '' McCain told CNN 's Wolf Blitzer about his former colleague . To understand the depth of the fallout between the two men one needs to understand how close the senators once were . McCain loaned his star power to Hagel 's first Senate campaign in 1996 , traveling to appear with him in Nebraska . When Hagel was elected to the Senate , the two men shared a bond over their service in Vietnam . In 1997 they attended a ceremony marking the 15th anniversary of the Vietnam Veterans Memorial . Speaking about his comrades in arms , McCain mentioned the `` unique bond that exists between us of which I am eternally proud . '' `` When I see them on the floor of the Senate or somewhere in the Capitol , I feel a little lift , '' he said . Hagel spoke of McCain 's service , declaring `` no one during this entire time ever gave more , or showed more courage , than John McCain . '' Five things Hagel may be asked about . Their friendship led to a close working relationship during the 2000 presidential campaign , when Hagel served as a loyal surrogate and campaign co-chair for McCain . Then , Hagel said his friend felt he owed the country his service . `` His life has been committed to something larger than he is , '' Hagel said after McCain suspended his campaign effort to make way for an ascendent George W. Bush . `` He 's a selfless person who 's given much to his country . '' Later that year , Hagel introduced McCain on the stage of the party 's convention with a giant embrace . Back in the Senate , the long-time friends and combat veterans both voiced early concerns about the handling of the Iraq war . But their views diverged as McCain came to support President Bush 's proposed troop surge in 2007 , a military decision that drew Hagel 's scorn . He famously called the proposal `` the most dangerous foreign policy blunder in this country since Vietnam if it is carried out . '' Why some conservatives are still going after Hagel . A source close to McCain said the friends just drifted apart as friends sometimes do , not because of policy differences . But even McCain acknowledged the change . `` I 've noticed over the years that our views on the United States of America and what we should be doing in the world have diverged rather dramatically , '' he said earlier this month . By McCain 's 2008 presidential run , Hagel was more in line with McCain 's anti-Iraq war opponent Barack Obama . The two traveled together on a Middle East Senate trip Obama used to beef up his foreign policy chops , and Hagel was never seen on McCain 's iconic Straight Talk Express campaign bus . Avlon : Reality check for Hagel bashers . Hagel and McCain spoke after the former senator 's nomination to the Defense Department . Afterward , McCain said he had concerns about Hagel 's positions on Iran , Iraq and Afghanistan . But citing their long friendship , McCain said he would not oppose Hagel before the hearing . `` Sen. Hagel and I are , are old friends and we had a very frank and candid conversation and I 'll be looking forward to the hearing and asking questions , '' McCain said on January 22 . `` I think that he should be given the opportunity of a hearing before any of us make a judgment . '' Hagel 's other war .
In 2000 , candidate McCain says Hagel would make a great Defense Secretary . In 2013 , McCain says he has concerns over Hagel 's nomination to the post . Comment: