Obama debuts second national security spot in two days

[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2008/images/07/16/art.obamaad0716.cnn.jpg caption="Obama’s second national security spot this week focuses on loose nukes."]
(CNN) — Barack Obama has released his second ad with a national security focus in as many days Wednesday, amid a week of events designed to highlight the presumptive Democratic nominee’s credentials on that front.

In the new 30-second spot, “Changing World” – which, like “America’s Leadership” Tuesday, does not mention Iraq and Afghanistan - Obama again highlights his work on the Senate Foreign Relations Committee to end the smuggling of loose nuclear weapons. The ad debuted on the same day he held a summit on the issue in Indiana, featuring prospective VPs Senator Evan Bayh and former Senator Sam Nunn as panelists.

“Forty years ago it was missile silos and the Cold War,” says the announcer, over images of missiles and other security threats. “Today, it’s cyber attacks…loose nukes…oil money funding terrorism.

“Barack Obama understands our changing world. On the Foreign Relations Committee, he co-sponsored a law to lock down loose nuclear weapons. As president, he’ll rebuild our alliances to take out terrorist networks, and fast-track alternatives so we stop spending billions on oil from hostile nations,” continues the announcer. “New leadership for a changing world.”

The ad will run on national cable starting Thursday.