Who is Chuck Hagel, Obama's controversial pick for Defense? President Barack Obama will nominate former Republican Senator Chuck Hagel to be his defense secretary and an announcement could come on Monday, sources familiar with the nomination process said. Hagel will have to undergo a rigorous selection process only weeks after the Obama administration backed down from a tough Senate confirmation battle over Susan Rice, the US Ambassador to the UN. She was Obama's first choice to replace Hillary Clinton as Secretary of State. However, Rice withdrew her name from consideration after drawing heavy fire from Republicans for remarks she made in the aftermath of a September 11, 2012 attack on the US mission in Benghazi, Libya. A confirmation battle is likely to take place in the Senate over whether former Nebraska senator and Vietnam veteran Hagel is fit for the job. Hagel has already been criticized on the right for his positions that some perceive as "dovish." There are also reservations among conservatives over whether he is a strong enough supporter of US ally Israel, his harsh criticisms of the W.Bush administration ("the lowest in capacity, in capability, in policy, in consensus - almost every area" of any presidency in the last forty years), the Iraq War (although he voted to authorize it) including the 2007 troop surge (""the most dangerous foreign policy blunder in this country since Vietnam, if it's carried out") as well as his calls for cuts in military spending (in 2011 Hagel called for the Pentagon's budget to be "pared down"). "This is an in-your-face nomination by the president to all of us who are supportive of Israel," South Carolina Republican Senator Lindsey Graham told CNN's "State of the Union.""I don't know what his management experience is regarding the Pentagon. Little, if any, so I think it's an incredibly controversial choice. On the other side of the aisle, Hagel's votes in favour of the Patriot Act and FISA - extending warrantless electronic surveillance - and past anti-gay comments for which he has apologized in December 2012 (Hagel had called Clinton-nominated prospective Luxembourg ambassador James Hormel "openly, aggressively gay" in 1998) are sure to trigger questions from civil libertarians and socially progressive voices on the left wing of the Democratic Party . President Obama's nomination of Hagel, a maverick but Republican nonetheless, bore traits of bipartisanship but the White House may have to put its weight in to ease the process. The White House said it is confident it can garner enough votes from both sides to get Hagel's nomination through the committee and win confirmation in the Democratic-led Senate. "The president wants him because he trusts him and he's an independent voice," a source close to the situation said. Obama and Hagel bonded in the 2000s over their shared opposition of the Iraq war. The pair even travelled to the war-torn country together in 2008. The nomination process is far from the first battle Hagel has had to fight in his life. Born in 1946, Charles Timothey "Chuck" Hagel grew up in a small town in rural Nebraska. There, he had at times to defend his three younger brothers against their alcoholic father's domestic violent bouts . Their abusive father died in his sleep in 1962. The cause of death was reportedly a heart attack, although Tom, the family's second eldest son, remembers empty whisky and pill bottles by the side of the bed. The family found his body on Christmas morning, when Chuck was aged 16. Six years later, both Chuck and Tom took part in the Vietnam War. They found themselves in the same infantry squadron, the first time that had ever happened to siblings in the US Army's history. Both returned with medals and distinctions but also severe wounds, receiving a collective total of five Purple Hearts. During the course of conflict, each brother saved the other's life. Unlike his brother Tom, whose war experiences made him a liberal, Chuck Hagel remained a conservative. Hagel entered political life in 1971 as a staffer for a Nebraska Congressman and was a campaign organizer for Ronald Reagan's victorious 1980 presidential campaign. In the 1980s, he briefly worked for fellow veterans as the deputy administrator of Veteran Affairs. After a successful business career, he became Nebraska Senator in 1996 and held the office until 2008. With Reuters More about: Barack Obama, Defence, Hillary Clinton, Washington