At a time when America’s ability to track and respond to dangerous international threats is already spread thin, Yemen as it exists today is on the verge of collapse amid reports that violence from Shiite Muslim rebels has forced the country’s top leaders to resign.

“The situation in Yemen changes hourly,” Defense Secretary Chuck Hagel said Thursday during a press conference at the Pentagon, as news broke that U.S.-backed Yemeni President Abed Rabbo Mansour Hadi had resigned.

Prime Minister Khaled Bahah also announced his resignation, saying Yemen’s leaders did not want to be dragged into “an unconstructive political maze,” according to the BBC.

Instability in Yemen, which had been divided into North and South Yemen before 1990, threatens both regional and world security. The country serves as home to al-Qaida in the Arabian Peninsula, considered the most potent offshoot of the al-Qaida extremist network and the one that most openly proclaims its desire to attack targets in the U.S. and elsewhere in the West. The Sunni Muslim group claimed credit for the Charlie Hebdo massacre in Paris earlier this month, though whether it was truly involved remains unclear.

Attacks by Houthi rebels – who are thought to be backed by Iran – within Yemen over the last year and the subsequent deterioration of security in the country have happened alongside the rise of the Islamic State group in Iraq and Syria. The extremist organization, also known as ISIS or ISIL, has become the central focus of fighting abroad for the U.S.

This increased attention on Iraq and Syria has detracted from America’s yearslong campaign to rid Yemen of dangerous extremist threats.

The number of drones conducting surveillance in the skies over Yemen remains guarded information, but armed drone strikes in the country have declined substantially in recent years, according to The Bureau of Investigative Journalism, which tracks reported attacks. There were as many as 106 strikes in Yemen in 2012, the bureau said. That dropped to as many as 32 in 2013, and as many as 33 last year.

U.S. officials also have described a consistent uptick of both manned and unmanned vehicles flying over Iraq and Syria in recent months, and CNN reported Thursday that more than 6,000 Islamic State group fighters have been killed in Iraq and Syria following six months of allied airstrikes.

Rep. Mac. Thornberry, R-Texas, confirmed Thursday morning the U.S. has dedicated less attention to threats in Yemen as a result of the greater dangers from the Islamic State group.

“We don’t have the ISR that we used to have, so when you have to move it to Iraq and Syria, you leave Yemen less covered than it used to be, because you have to make choices and that increases danger to that country,” the new chairman of the House Armed Services Committee said while meeting with a group of reporters.

Thornberry was describing the effects of congressionally mandated budget cuts known as sequestration, and used the military’s limited number of information-surveillance-reconnaissance – or ISR – drones as an example of the concrete problems facing the U.S. if fellow members of Congress don’t repeal the cuts.

“Yemen is the place from which the most serious threats against our homeland have emanated,” he later clarified. “We still have a limited number of ISR available, so if you have to do more – we had nothing, especially in Iraq and Syria, so if you’re going to do something there it has to come from somewhere.”

“Some of it invariably has to come from Yemen. I’m not saying that’s a cause of the Houthi takeover. There’s a lot of very difficult, dangerous places in the world and the more of them there are, the tighter we’re stretched,” he says.

Thornberry declined to comment on specifically how many fewer U.S. drones and other assets may be deployed to Yemen. But he stated there is “a lot less activity there than there used to be.”

Yemen's situation is indicative of an even greater quandary confronting the U.S., as extremist networks aim to spread abroad during lean financial times at home.

“Deployable ISR assets are a zero-sum game,” says Chris Harmer, a senior naval analyst at the Institute for the Study of War. “If you relocate assets away from the Red Sea, Gulf of Aden, Somali Basin and the Arabian Gulf into Iraq and Syria, you start to lose some of the situational awareness of what is happening with Iran’s maritime smuggling campaign.”

That example, he says, accounts for the supplies Iran is able to funnel to the Houthis in Yemen, or to Hamas operatives in Sudan who can transfer them to the Gaza Strip.

Effective situational awareness extends beyond simply observing what is happening at any given moment, but also to developing what the military calls a “pattern of life.” Analysts need to know what potential insurgents or terrorist groups have been doing for weeks or months, to be able to contextualize whether their current activity presents a real danger or threat. The military can then develop the best way to fight back.

Interrupting that process means those involved must start again from the beginning.

“ISIS is, and should be, the priority for U.S. collection and analysis efforts right now,” Harmer says. “But they are by no means the only bad actor.”

The U.S. is left, then, with a situation it has seen many times before. Somalia, for example, had been the target of U.S. special operations forces in the 1990s, before it officially descended into its current status as a failed state.

The Islamic State group’s current battlegrounds represent perhaps closer templates of what Yemen could eventually become. New leadership in Iraq under Prime Minister Haider al-Abadi may be able to keep the country from shattering along ethnic lines. Syria, however, will likely never look the same after four years of intense and bloody civil war between the regime of President Bashar Assad and a highly factional group of opposition fighters and extremists.

Yemen, at the moment, could go either way.

“We were well aware of the danger and uncertainty and what was going on there before today,” Hagel said Thursday.