The Vietnam War veteran picked to lead the Pentagon, Chuck Hagel, sought to reassure lawmakers Thursday that he was ready to back military action if necessary against Iran or other adversaries. Facing tough questions from some senators at his confirmation hearing, Hagel said in his opening remarks that he wanted to keep America\'s armed forces the strongest in the world and that he supported using military force to safeguard the country\'s interests. \"We will not hesitate to use the full force of the United States military in defense of our security,\" Hagel said before the Senate Armed Services Committee. \"But we must also be smart, and more importantly wise, in how we employ all of our nation\'s great power.\" Hagel, who was wounded and decorated for his combat tour with an infantry unit in Vietnam, broke ranks with his fellow Republicans over the Iraq war and has come under fire for some statements and senate votes on Israel and Iran. The blunt-speaking former senator from Nebraska has said military action should be a last resort and has sometimes expressed impatience with Israel while expressing support for direct talks with Iran over its nuclear program. But Hagel told lawmakers he endorsed President Barack Obama\'s stance on Iran\'s nuclear program, with military force as an option if diplomacy fails. \"I am fully committed to the president\'s goal of preventing Iran from obtaining a nuclear weapon, and -- as I\'ve said in the past many times -- all options must be on the table to achieve that goal,\" he said. Hagel has pursued a charm offensive in recent weeks, seeking to reassure Republicans and Democrats in a flurry of meetings. But the ranking Republican on the Senate Armed Services Committee said he was not convinced, portraying Hagel as ready to appease Tehran. \"His record demonstrates what I view as a lack of steadfast opposition to policies that diminish US power and influence throughout the world,\" Senator Jim Inhofe, the ranking Republican on the Senate Armed Services Committee, said at the start of the hearing. \"Too often, it seems, he\'s willing to subscribe to a world-wide view that is predicated on appeasing our adversaries while shunning our friends.\" But despite the harsh criticism and a conservative media blitz against Hagel, the White House is optimistic that the Senate will approve his nomination in the end, albeit with little support from the Republican minority. A fellow Vietnam veteran, Senator John McCain, has taken Hagel to task over his opposition to the troop surge in Iraq, which Hagel at the time referred to as \"the most dangerous foreign policy blunder in this country since Vietnam.\" Inhofe and other Republicans also say Hagel appears ready to gut military spending, citing his comment that the Pentagon\'s budget was \"bloated.\" If confirmed, Hagel would be the first Vietnam veteran to serve as Pentagon chief, as well as the first to come from the military\'s enlisted ranks. Former senator Sam Nunn, once a powerful voice in Congress on military issues, introduced Hagel at the hearing, praising him as an excellent choice to lead the Pentagon. Hagel still has bits of shrapnel in his chest from his wounds in Vietnam and Nunn said Hagel\'s war experience will help inform his decisions as defense secretary. \"War for Chuck Hagel is not an abstraction,\" Nunn said.