Susan Rice is the UN Ambassador and Republicans claim that she should not be promoted, referencing her response to September's deadly attack on the US consulate in Libya. Consequently, Republicans is drawing more critical attention and is calling for a committee to examine the Libya attack.
Obama states that “When they go after the UN ambassador, apparently because they think she's an easy target, then they've got a problem with me”
In light of the September 11 assault on the US mission in Benghazi, Ms Rice has labelled the assault as an unexpected protest over an anti-Islamic film created in the US. Subsequently, the Obama administration alleges that al-Qaeda linked militants are the cause of the attack.
On Wednesday, Sen John McCain to promised to obstruct any action to appoint Ms Rice to replace Mrs Clinton as America's top diplomat.
"This administration has either been guilty of colossal incompetence or engaged in a cover-up," he said on the Senate floor.
Lindsey Graham, another Republican senator, said he has no confidence or trust in Ms Rice.
President Obama said: "If Senator McCain and Senator Graham and others want to go after somebody, they should go after me.
"But when they go after the UN ambassador, apparently because they think she's an easy target, then they've got a problem with me."
"To besmirch her reputation, is outrageous," he added.
Sen Graham demonstrated no act of apology or regret for his statements.
"Mr President, don't think for one minute I don't hold you ultimately responsible for Benghazi," he said in a statement.
"I think you failed as commander in chief before, during and after the attack.""
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