The registration requirement was suspended in April 1975. It was resumed again in 1980 by President Carter in response to the Soviet invasion of Afghanistan. Registration continues today as a hedge against underestimating the number of servicemen needed in a future crisis. Source: the official website of the Selective Service Administration.

and

Mr Obama was asked by George Stephanopoulos of ABC's "This Week" programme whether he'd ever thought about military service and replied: "You know, I actually did. I had to sign up for Selective Service [a means of conscription in case of war] when I graduated from high school.

"And I was growing up in Hawaii. And I have friends whose parents were in the military. There are a lot of Army, military bases there.

"And I actually always thought of the military as an ennobling and, you know, honourable option. But keep in mind that I graduated in 1979. The Vietnam War had come to an end. We weren't engaged in an active military conflict at that point. And so, it's not an option that I ever decided to pursue."
Source: The Telegraph

I am puzzled. Obama states that he graduated from high school in 1979. And, Obama states that he registered for selective service when he graduated from high school. But, there was no Selective Service registration in 1979. Perhaps it was a slip of the tongue, having no teleprompter or notes to consult. He seems not to have anticipated the question. He is not good at thinking on his feet when forced off his talking points: witness his mispeak "my Muslim faith" in the same interview.

If George Stephanopoulos can rattle Obama into misstatements, how will B.H. Obama do with Tsar Vladimir?