David Jackson

USA TODAY

Aides to President Obama said Monday he is not blaming intelligence officials for underestimating the threat of the Islamic State and overestimating the ability of Iraqi security forces to fight them.

Intelligence analysis is "a difficult business, and, ultimately, at the end, becomes a prediction," said White House spokesman Josh Earnest.

Some Republican lawmakers, meanwhile, pushed back on Obama's comments that the spread of the Islamic State -- also known as ISIL -- into large parts of Syria and Iraq came as a surprise.

"I think our head of the intelligence community, Jim Clapper, has acknowledged that I think they underestimated what had been taking place in Syria," Obama said in a 60 Minutes interview aired Sunday.

Obama also echoed Clapper's statement that "we overestimated the ability and the will of our allies, the Iraqi Army, to fight."

Sen. John McCain, R-Ariz., told USA TODAY on Monday that intelligence agencies in fact forecast the rise of ISIS, and described Obama's comments as "the dog ate my homework kind of routine."

McCain blamed the expansion of the Islamic State on the U.S. failure to keep a residual force in Iraq after the end of combat operations.

"When the president decided we were not going to leave a sustaining force in Iraq ... those of us who knew the area well knew the situation was going to deteriorate," McCain said.

At the White House, Earnest said that the president retains confidence in Clapper and the intelligence community.

"Ultimately, the president is commander-in-chief," Earnest said. "And he's the one who takes responsibility for ensuring that we have the kinds of policies in place that are required to protect our interests around the globe."