Robert Gates: U.S. can't beat Islamic State militants without 'boots on the ground'

Poll: 41 percent of Americans approve of president's handling of terrorism, a new low

Former U.S. Defense Secretary Robert Gates criticized President Barack Obama's strategy to "degrade and destroy" the Islamic State (also known as ISIS and ISIL) without sending in ground troops.

"The reality is they're not going be able to be successful against ISIS strictly from the air, or strictly depending on the Iraqi forces, or the peshmerga, or the Sunni tribes acting on their own," Gates said in an interview on "CBS This Morning" on Wednesday. "So there will be boots on the ground if there's to be any hope of success in the strategy. And I think that by continuing to repeat that [he won't send in ground troops], Obama in effect traps himself."

Gates is not alone in his criticism of the president. According to a new CBS News/New York Times poll released on Wednesday, 57 percent of Americans don't think Obama is being tough enough in dealing with the Islamist militants, while 31 percent think his approach is about right.

The poll also found Obama's approval rating when it comes to terrorism is at a record low: 41 percent approve of his handling of the threat of terror — down 12 percentage points since March. Compare that to May 2011, after the killing of Osama bin Laden, when 72 percent approved.

"We've been at war with al-Qaida for 13 years. We have dealt them some terrible blows, including the killing of Osama bin Laden," Gates said. "But I don't think anybody would say that after 13 years we've destroyed or defeated al-Qaida."

Gates to Couric: White House should go look in the mirror

He added: "To promise that we’re going to destroy ISIS or ISIL sets a goal that may be unattainable, as opposed to devastating it or, as the vice president would put it, following them to the gates of hell and dealing them terrible blows that prevent them from holding territory. Those are probably realistic goals.”

Since retiring as defense secretary in 2011, Gates has been a vocal critic of the administration.

In his memoir, "Duty," published earlier this year, Gates took aim at political aides in the Obama White House for attempting to micromanage the Pentagon and allowing politics to trump the national interest in policy debates. He also accused Obama aides of circumventing the military chain of command.

He was particularly critical of Vice President Joe Biden, who he wrote has been “in the wrong on nearly every major foreign policy and national security issue over the past four decades."

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