Scott Pelley: Obama's Afghanistan address a message to Iran, Pakistan

(CBS News) "CBS Evening News" anchor Scott Pelley, who's reported from the front lines of the war in Afghanistan for more than a decade, said on "CBS This Morning" Wednesday that President Obama's address from the war zone Tuesday night was a message not just to Americans but also to Iran and Pakistan, which share a border with Afghanistan.

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Mr. Obama made an unannounced visit to the country Tuesday, during which he signed a long-term security agreement with Afghan President Hamid Karzai that allows for the United States to potentially keep military forces in the country in a support role until 2024, a decade after the 2014 deadline for U.S. combat troops to go home. Pelley told Gayle King and Charlie Rose the continued American presence is intended to soothe Pakistan's nerves about the Afghan government's military.

"The Pakistanis are very concerned about this army we're building up in Afghanistan, about half a million men trained and equipped by the United States," said Pelley. "Afghanistan, as you know, is a completely destitute country. It could never afford to keep that army in the field, so the Pakistanis are saying, 'What's going to happen if the United States pulls out? We're going to have half a million armed men unemployed on our border.' So, what this signal was from the president was to say, 'We're pulling our combat troops out by 2014, but we're not going anywhere,' reassuring the Pakistanis, warning the Iranians on the other side of Afghanistan we're going to be here for the long haul."

Above, watch Scott Pelley break down President Obama's stealth trip to Afghanistan