Chuck Hagel steps down as US defence secretary

US defence secretary Charles (Chuck) Hagel has resigned in less than two years after President Barack Obama appointed him on the all powerful post, amidst increased unease at the White House over US failure in tacking international crises, both political and military.

Hagel is reported to have resigned under pressure from an administration that wanted a more robust and assertive US response to global issues.

Announcing his resignation, President Barack Obama described Hagel as ''an exemplary defence secretary'' who had overseen major changes in the American defence forces.

''I did not make this decision lightly. But after much discussion, the President and I agreed that now was the right time for new leadership here at the Pentagon,'' he said after the President announced his resignation.

Chuck Hagel, the only Republican in the top administration, was chosen as defence secretary because President Obama wanted someone who would quietly implement the administration's policy, but he had to quit exactly for that.

Hagel took credit for achieving a successful transition in Afghanistan, for blunting the momentum of the barbaric forces of ISIL and helping people affected by diseases and natural calamities around the world.

Most importantly, he said, ''We have helped keep this country and our fellow citizens safe. We have sustained the blessings of liberty our ancestors secured and upheld the oath we took.''

America has sustained an all-volunteer force that has been in war for 13 years, during which US has bolstered enduring alliances and strengthened emerging partnerships, ''all the while setting in motion important reforms that will prepare this institution for the challenges facing us in the decades to come.''

''That work will continue. It must continue. The world is still too dangerous, the threats too numerous, for us to lose focus. And even as I promised the President my full support going forward, so, too, do I promise that I will work hard to support you right up until my last day in office. I owe you that,'' he said as he bid farewell to the Pentagon.

While Hagel did not make any big mistakes or lose the confidence of the military, he often seemed at differing wavelengths with top generals, especially those focused on the battle against Islamic State militants in Iraq and Syria.

''I could never tell what his opinion was on anything,'' said a senior administration official involved in national security policy. ''He'd never speak... The key comment, the insightful approach - that never came out of him.''

Hagel liked to work behind the scenes to lessen the impact of budget cuts on the military's ability to fight future wars and on the families of those in uniform.

 ''Hagel tried to play a behind-the-scenes role on tough issues - the [budget cuts], sexual assault, ending two wars,'' said Vikram Singh, a former top Pentagon official and a vice president at the Center for American Progress. ''He didn't want to be a larger-than-life secretary.''

 ''He understands our men and women like few others, because he stood where they stood,'' Obama said of Hagel, who served as an Army sergeant in Vietnam. ''He's been in the dirt and he's been in the muck. And that's established a special bond.''

But, Hagel seems to have been at a loss when strategising moves against the Islamic State of Iran and Syria, forcing Obama to look for to seek a defense secretary who was more at ease with the changing global environment.

Hagel's replacement is unlikely to turn the tide in favour of America any further either in Iraq, Syria or Afghanistan, where the war on land has to be fought on land itself and not from the air as America has learnt sufficiently from its war in Vietnam.

President Obama had to double the number of US military advisers in Iraq and extend its role in Afghanistan, where Obama was committed to ending the war.

Instead of taking pressure off the president, it's likely that the process of Hagel's replacement will create more political headaches for the President in the near term. More importantly, it could provide critics ammunition to attack the President's policies in Iraq, Syria, Afghanistan and Ukraine.