The timing of Chuck Hagel’s resignation as secretary of defense may have been a surprise, but the fact that he was on his way out has been rumored for weeks. The real issue is why he either stepped down or was forced to leave after such a comparatively short time in office.

Hagel’s departure may bring about some short-term political gains, but in the long run it will not be good for the administration, the Pentagon or the country.

There are two interrelated reasons for his exit. First, the Obama administration needed to have a high-ranking figure take the fall for the emergence of the militant group, Islamic State in Syria and the Levant (often called Islamic State), and the initial disjointed White House response to the threat.

Second, Hagel’s ability to influence administration policy was hampered from the start by his contentious confirmation hearing, which seemed to catch the White House by surprise. Then, as the White House took increasing control of the foreign policy decision-making process, Hagel’s influence diminished markedly.

Was Hagel fired because he was not qualified for the post? Administration sources have reportedly suggested that the Pentagon needed someone with a “different set of skills” to tackle the threat of Islamic State extremists in Iraq and Syria.

This, however, ignores Hagel’s on-the-ground combat experience as a soldier and a leader. He enlisted in the Army infantry during the Vietnam War, receiving two Purple Hearts and the Army Commendation Medal, among other decorations. To suggest that he doesn’t have the skills or experience to guide the Pentagon in the fight against Islamic State extremists strains credulity.

Beyond the fight on the ground, Hagel also understands the big picture of U.S. national security and foreign policy. As a two-term senator from Nebraska, Hagel showed astute foreign policy acumen, especially regarding the Middle East and Afghanistan. He was one of the first to recognize that Prime Minister Nouri al-Malaki’s shortcomings jeopardized Iraq’s stability, and consistently argued that the Iraqis would have to take responsibility for their own future.

Hagel also brought considerable private- and public-sector management expertise to the Pentagon, as both the founder of a successful cell phone company and the deputy administrator of the Veterans Administration.

Was Hagel dismissed because he failed to grapple with the problems the Pentagon faced? Hardly. Unlike several of his predecessors, he adjusted the military budget to reflect the spending reductions mandated by sequestration; took forceful action to deal with the problems of sexual violence and suicides in the ranks, and began overhauling a dysfunctional nuclear-weapons complex.

In addition, Hagel capably managed the drawdown of U.S. troops in Afghanistan, and set the rules of conduct for American troops as they take on a train, advise and assist role there next year.

Will appointing a new defense secretary have much impact? Not really. When he or she is confirmed sometime next year, the current muddle-through approach to Islamic State extremists, Iraq, Syria and the Kurds will still be continuing.

The Pentagon’s fiscal year 2016 budget will have already been drafted, and maybe sent to Congress. So that leaves little room for a new secretary’s imprint. The new Pentagon chief will have a chance to have an impact on the fiscal year 2017 defense budget. But without knowing who the president will be in 2017.

Even on the managerial front, the new secretary will not have the opportunity to bring in his or her own appointees to help run the Pentagon, leaving little hope for a continued push to reform the Defense Department’s approach to sexual assault or improve the acquisitions process.

Ultimately, finding a new secretary may be difficult. Like Hagel’s 23 predecessors, none of the people rumored to be potential replacements bring a similar combination of military, managerial and political experience to the job. Moreover, few qualified people would want to leave their jobs for a post that requires a sure-to-be difficult Senate confirmation hearing and offers a tenure of less than two years.

With the 2016 presidential election campaign in full swing shortly after a new defense secretary would take office, the window for wielding influence over the Pentagon and our national security policy is likely to be very brief.

Americans must hope that Obama considered all these factors before he asked for Hagel’s resignation.

PHOTO (TOP): Defense Secretary Chuck Hagel (L) listens as President Barack Obama announces Hagel’s resignation at the White House in Washington, November 24, 2014. REUTERS/Kevin Lamarque

PHOTO (INSERT 1): Defense Secretary Chuck Hagel speaks to U.S. troops at Camp Bastion, Afghanistan, December 8, 2013. REUTERS/Mark Wilson/Pool

PHOTO (INSERT 2): Senator Chuck Hagel (R-Neb.) testifies during a Senate Armed Services Committee hearing on his nomination to be Defense secretary, on Capitol Hill in Washington, January 31, 2013. REUTERS/Kevin Lamarque