Story highlights Georgia runoff race is increasingly focused on national security

Ossoff trying to sell himself as an independent, moderate voice

Washington (CNN) Democrat Jon Ossoff's latest television ad has all the hallmarks of a politician put on his heels by his opponents' attacks on his national security bona fides.

The ad features Ossoff talking straight into the camera. And instead of his own message, he is responding to one that a Republican super PAC spent millions to put on the air in Atlanta. "Let's put this to rest once and for all," Ossoff says as the 30-second spot begins.

He goes on to denounce ISIS as "evil," declare that "we have to stop them" and direct viewers to a beefed-up national security section on his campaign website . The website now features six sections -- covering military funding, intelligence sharing, battling ISIS, fighting radicalization online and more -- that weren't there a month ago.

Just one week from the conclusion of the most expensive House race in history, the air battle between Ossoff and Republican Karen Handel is increasingly focused on national security.

The dynamic emerged locally despite the national view that the race is a referendum on President Donald Trump. Ossoff -- careful not to alienate persuadable voters in a heavily Republican district -- rarely discusses Trump, instead selling himself as an independent, moderate voice. That has created an opening for Republicans to hammer him on issues that are important to their base and that aren't directly tied to the President's popularity.

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