Hagel opposes unilateral sanctions against Iran, and while his multilateralist approach fits with President Obama's, Hagel's votes against extending sanctions on Iran could cost him favor with Israel advocates.
The Republican Jewish Coalition aired a list of grievances against Hagel in December, after his name first became seriously floated for the position, with Executive Director Matt Brooks saying the former senator's "statements and actions regarding Israel have raised serious concerns for many Americans who care about Israel."
Weekly Standard editor William Kristol, who also leads the Emergency Committee for Israel, lambasted Hagel in an editorial in his magazine, citing Hagel's "anti-Israel, pro-appeasement-of-Iran bona fides," and, "record of consistent hostility to Israel over the last decade."
Shortly after Obama made his announcement, Senate Majority Leader Eric Cantor released a statement saying he was "profoundly concerned and disappointed" with Hagel's nomination.
"Senator Hagel's incendiary views of Israel are only the tip of the iceberg. On Iraq, Afghanistan, Syria, Iran and defense spending, Hagel's reported views call into question his judgment about the most important matters facing our national security. Taken together, Hagel's views represent a call for a broad retreat from the preeminent role America has played, and must continue to play, in the world during a period of profound tumult and instability," Cantor, R-Va., wrote.
A Republican LGBT activist group has also criticized Hagel for his record on gay rights, for – among other things – opposing the repeal of Don't Ask, Don't Tell.
In a 2011 interview with the National Journal, Hagel said "a dangerous, toxic intolerance of other people's opinions" had tainted American politics.
Though he has largely shown support for President Obama, he called the president's health care law his "biggest mistake," saying it sapped him of "a good amount of his political capital and goodwill going in."
By picking Hagel, a Republican, Obama is seen as making a stab at bipartisanship – something most Americans agree Washington is sorely lacking these days.
Immediately after Obama announced his nomination, former Secretary of State Colin Powell sent out a statement endorsing his choice.
"Chuck displays his courage in many ways. You can always count on him to analyze a difficult situation and take a position that reflects his best judgment. I believe that more than ever we need that kind of independent and bold leader who thinks in and out of the box. He is the kind of leader needed by the Department of Defense to deal with the strategic and resource challenges it will be facing over the next several years."
Like Obama, Powell urged the Senate to confirm Hagel "as soon as possible."