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Flash Points: What's next for war-torn Yemen?

Yemen teeters on the edge of a civil war, as Shiite Houthi fighters continue their violent bid for territory in the Sunni stronghold of Aden.

The Houthi forces' encroaching power is enough to make Saudi Arabia, the country leading air strikes against the rebel group, consider putting boots on the ground to fully enter the conflict.

"The Houthis are a vicious fighting force, they've taken a vast swath of territory and they've moved further into the south than anyone had anticipated," CBS News Senior National Security Analyst Juan Zarate said. "The Sunni-backed elements in Yemen are under threat enough to suggest that you're going to have to put in ground troops."

Yemen is now the battleground for the latest -- and one of the bloodiest -- conflicts in the proxy war playing out between Iran, which backs the Houthis, and the rest of the Sunni Arab world.

"It sets the battle lines between the Sunni-backed forces that is represented by this coalition," Zarate said, referring to the alliance composed of the Gulf monarchies and other Sunni-majority countries like Pakistan and Egypt. "It sets that coalition up against Iran, which is backing the Houthis, and where these countries -- the Saudi-led coalition -- see Iranian influence growing."

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Yemen's fate only continues to grow murkier. After President Abed Rabbo Mansour Hadi fled the country in March, one of the last Sunni holdouts -- the southern port city of Aden, where the U.S.-backed Hadi had set up a makeshift seat of government after Houthi forces drove him out of the capital -- has fallen victim to Shiite sieges. Al Qaeda in the Arabian Peninsula (AQAP), taking advantage of the impoverished nation's disarray, has also continued to establish footholds in the country.

Despite the escalation of violence, few countries outside of the Middle East are involving themselves in the fray. Though some U.S. lawmakers -- like Senate Intelligence Committee Chair Richard Burr, R-North Carolina, who expressed his fear on CBS News last week that Yemen is "on the verge of a civil war" -- have given hesitant opinions about the ongoing bloodshed, the Sunni-backed coalition is largely on it its own.

"It's a coalition of the willing without the U.S. leading it," Zarate said. "And frankly without the U.S. being a partner of it."

But the independence of these Arab nations dealing with the conflict without U.S. intervention could prove to be a double-edged sword.

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While President Obama has encouraged Middle East countries to take the wheels when it comes to stabilizing the violence in the region, it also means that Sunni allies are taking action with lessened regard for American interests.

"The moment that the U.S. isn't leading, isn't guiding, isn't shaping a coalition, you're now leaving the battlefield and the geopolitics to other players," Zarate said. "These are allies, but they may not listen to us at the end of the day... we've got to be careful what we wish for here."

Zarate cautions that it could be "the beginning of a deeper regional war."

"With these countries now worried about an emboldened Iran -- perhaps even with nuclear capabilities -- this perhaps inflames that tension in that regional war and could become a broader conflagration."