Democratic presidential candidate Bernie Sanders speaks during a recent campaign event at Wartburg College in Waverly, Iowa. (Scott Morgan/Reuters)

Democratic presidential hopeful Bernie Sanders, whose campaign has largely focused on domestic issues, is touting his foreign policy judgment in a new television ad, which began airing Wednesday in Iowa and New Hampshire.

The Vermont senator has acknowledged that he has less foreign policy experience than former secretary of state Hillary Clinton, and he normally devotes only a few minutes of his hour-long stump speech to international affairs.

But in the 30-second spot, Sanders seeks to make the case that his judgment is solid, and he vows that as president, he would “defend this nation but … do it responsibly.”

[Sanders prepares to challenge Clinton on Super Tuesday and beyond]

Sanders also highlights his 2002 vote on invading Iraq, calling it “the right vote.” The ad makes no mention of Clinton, but on the campaign trail in recent days Sanders has called attention to their divergent votes. As a senator representing New York in 2002, Clinton voted to authorize force in Iraq. She has since said that was a mistake.

In the ad, Sanders also says that the Islamic State terrorist organization must be destroyed but that “we should not do it alone.”

“We need an international coalition, with Muslim boots on the ground, fighting with our support,” Sanders says.

[Clinton blew ‘the most crucial foreign policy issue,’ Sanders says in Iowa]

Sanders’s approach to fighting ISIS came under attack this week from a group of foreign policy experts supporting Clinton.

“His lack of a strategy for defeating ISIS -- one of the greatest challenges we face today -- is troubling,” the group of 10 wrote in a letter released Tuesday. “And the limited things he has said on ISIS are also troubling.”

In particular, they pointed to a Sanders statement suggesting that Iran should send more troops to Syria and join in a military coalition with Saudi Arabia.