Vice President Joe Biden said American aid worker Jessica Buchanan's health was the reason President Obama authorized last night's special operations rescue operation in Somalia.

"They said it was the time, the opportunity.  Jessica's health was, was in a word, 'failing,' and they concluded they should go at this time and the president gave a go," Biden told me on "GMA."

He wouldn't go into details, but Biden said "it's safe to say" the mission went without a hitch.

"One of the things we know from before with the bin Laden raid is the operational details are better not to be laid out and I'll let the Pentagon decide to do that," he said.

"I've been in country, in Afghanistan, in Iraq with these guys, these Special Operations Forces, they are absolutely the most incredible…it just takes your breath away, their capacity, and their bravery, and their incredible timing.  These guys are amazing, and women, are amazing," Biden added.

As our Martha Raddatz reported the Navy SEALs parachuted into the compound to rescue both Buchanan, 32, and her Danish co-worker Dane Poul Hagen Thisted, who were captured in October.

The president and vice president were sitting on quite a happy secret at the State of the Union last night. As the president came down the aisle he turned to his Secretary of Defense, Leon Panetta, and said "Good job tonight." Perhaps in reference to the rescue mission.

Biden said he monitored the rescue operation from the situation room last night, calling it a "good moment."  Following his State of the Union address Biden said President Obama called Buchanan's father to tell him the mission was a success.

"The president had the great privilege of being able to call her dad to say she was safe when she was out of the country and in good hands," he told me.

- George Stephanopoulos