Houthi's March

How does an all-out, Sunni vs. Shia, war on the Arabian Peninsula sound to you?

The turmoil in Yemen grew into a regional conflict Thursday, with Saudi Arabia and its allies bombing Shiite rebels allied with Iran, while Egyptian officials said a ground assault will follow the airstrikes.

Iran denounced the Saudi-led air campaign, saying it "considers this action a dangerous step," and oil prices jumped in New York and London after the offensive.

The military action turned impoverished and chaotic Yemen into a new front in the rivalry between Saudi Arabia and Iran.

Why would the oil prices jump? Take a look at a map of the region:

Location, location, location

You can do a lot to disrupt commerce on the Red Sea if you control Yemen. And for now, the Shias under the direction of Abdul Malik al-Houthi are making the standard threats:

Rebel leader Abdul-Malik al-Houthi angrily accused the United States, Saudi Arabia and Israel of launching a "criminal, unjust, brutal and sinful" campaign aimed at invading and occupying Yemen.

"Yemenis won't accept such humiliation," he said in a televised speech Thursday night, calling the Saudis "stupid" and "evil."

The Houthis, who have taken over much of the country, mobilized thousands of supporters to protest the airstrikes, with one speaker lashing out at the Saudi-led coalition and warning that Yemen "will be the tomb" of the aggressors.

The aim of his patrol is not a question rather droll. And, as Walter Russell Mead explains, the stakes are pretty high:

Events in Yemen continue to accelerate much faster than many experts predicted, and the potential for widespread sectarian war between Sunni and Shi’a grows more acute by the day. In some ways this portends even more trouble than ISIS’s fight against Iran’s proxies in Syria and Iraq: that fight is both bloody and strategically important, but ISIS is also an enemy of the Sunni powers (whose rule it wants to overthrow). Now, the Saudis and their allies are clearly prepared to confront Iran’s allies head-on.

I don't see a lot of good options right now.