Multi-National Force – Iraq

Casey served as the senior coalition commander in Iraq from June 2004 to February 2007. He replaced Lieutenant General Ricardo S. Sanchez.^[4] Casey's goal was to encourage the Iraqis to take ownership of their problems and responsibility for their own security. For his part as a military commander, he focused on training Iraqi forces, limiting the role of American forces, and transferring the burden for providing security to Iraqi forces. Meanwhile, U.S. diplomats would focus on building and strengthening the Iraqi government and help the Iraqis hold elections. He expressed his view that a large and intrusive American presence in Iraq would not solve the political and security problems in that country and could even fuel the insurgency.

In 2005, Casey was hopeful that the December 2005 Iraqi elections could lead to a more unified and moderate Iraq which—in conjunction with the training of Iraqi security forces—could pave the way for U.S. troop reductions in early 2006.^[5] In August 2005, Casey used specific troop numbers in his public discussion of a possible drawdown. He said the troop level of 138,000 could be reduced by 30,000 in the early months of 2006 as Iraqi security forces took on a greater role. President George W. Bush publicly called the talk "speculation" and rebuked the general. The bombing of the al-Askari Mosque, a sacred Shia religious site in Samarra, is believed to have stoked sectarian tensions and derailed coalition plans to speedily transfer significant security responsibility to the Iraqi government by the end of 2006.^[6]

In January 2007, Casey implied his opposition to a troop surge:

... the longer we in the U.S. forces continue to bear the main burden of Iraq's security, it lengthens the time that the government of Iraq has to take the hard decisions about reconciliation and dealing with the militias. And the other thing is that they can continue to blame us for all of Iraq's difficulties, which are at base of their problems. It's always been my view that a heavy and sustained American military presence was not going to solve the problems in Iraq over the long term.^[7]

Army Chief of Staff

In January 2007, President George W. Bush nominated Casey for elevation to Chief of Staff of the Army. Opposition to the nomination came from Senators John McCain and Lindsey Graham who questioned Casey's leadership in Iraq, with McCain's criticisms focused on Casey's "optimistic and rosy scenarios" of progress in the Iraq War.^[8][9] In spite of this, the Senate confirmed his nomination on February 8, 2007, with a bipartisan vote of 83–14.^[10]

On February 10, 2007, Casey relinquished command in Iraq to General David Petraeus. Casey officially succeeded General Peter Schoomaker as Chief of Staff of the Army on April 10, 2007.

As the 36th Chief of Staff of the United States Army from April 2007 to 2011, Casey led what is arguably the world's largest and most complex organization—1.1 million people strong, with a $200+ billion annual budget—during one of the most extraordinary periods in military and global political history. He became Chief of Staff of an Army that was stretched from 6 years of continuous war. Over his tenure he stabilized and transformed the army to meet the challenges of the 21st century while continuing to meet the demands of two wars. Casey transformed an army trained and prepared for conventional war, to an agile force more suited to modern challenges.

Casey accelerated the growth of the army, instituted Retention Bonuses for young officers, increased the funding for soldier and family programs, improved the way the army cared for its wounded soldiers and surviving family members and drove down the stigma associated with behavioral health counseling to stabilize an army stretched by war. He also improved the leadership training for the army's General Officer Corps, advanced the transformation of the army's business and decision-making processes, moved the army onto a rotational deployment program much like the Marine Corps' and oversaw a substantial improvement in the capabilities of the Army National Guard and Army Reserves.

In the immediate aftermath of the 2009 Fort Hood shooting committed by United States Army psychiatrist Nidal Hasan, Casey expressed concern about jumping to conclusions before the investigation was completed, telling CNN's John King that "this increased speculation could cause a backlash against some of our Muslim soldiers" and "As great a tragedy as this was, it would be a shame if our diversity became a casualty as well."^[11] Several months later, in a February 2010 interview, Casey said: "Our diversity not only in our Army, but in our country, is a strength. And as horrific as this tragedy was, if our diversity becomes a casualty, I think that's worse."^[12][13]