In this installment of our series “Issues That Matter,” we take a closer look at South Korea and the escalating standoff over North Korea’s nuclear program.

South Korean President Park Geun-hye was forced from office Friday, plunging a key U.S. ally into political turmoil. It brings new uncertainty to the region at a time of growing provocations from North Korea following the North’s launch of four missiles into the Sea of Japan on Monday. Pyongyang claimed the launch was a drill for striking American military bases in Japan.

Former U.S. ambassador to South Korea Christopher Hill said the U.S. military has the capability for a preemptive strike against North Korea. However, he warned such a strike could spark a wider war resulting in a high number of civilian casualties.

“The problem is some 20 million South Koreans are in the northern part of South Korea within range of 14,000 artillery tubes. And we have really state-of-the-art so-called ‘counterbattery fire,’ that is, as soon as one of these artillery tubes appears, we can hit it very quickly,” Hill, now dean of the Josef Korbel School of International Studies at the University of Denver, said Friday on “CBS This Morning.” “The problem is, you can’t usually hit it before it’s fired off a weapon, fired off a shell. So you’re looking at the possibility, the very distinct possibility in the event of a war of a lot of civilian casualties. So people shouldn’t talk easily about war in the peninsula… even a preemptive strike. It’s a very small place.”

But Hill said a preemptive attack shouldn’t be taken off the table as North Korea’s nuclear progress becomes a growing concern.

“They have about enough plutonium for about 20 weapons. Although we don’t know their design yet, but we know they’ve been working on a warhead,” Hill said. “Secondly, what we’re seeing the last few days in terms of these medium-term, medium-range missiles is solid fuel. That means they can stand them up and shoot them off before we can really target them, so this is a real concern as they move forward.”

The solid fuel would make it more difficult for the U.S. to launch a preemptive strike as well, he said.

“They can stand these things up in the woods somewhere, they can be on mobile launchers. It’s quite different from the old thing of putting them up and sticking a hose into the side and putting in some liquid fuel,” Hill said.

In addition to the North Korean threat, South Korea is undergoing a major political transition, with President Park being ousted from office. Violent protests followed the court’s decision to remove her over a corruption scandal. Whoever replaces her will also have a major impact on relations with the North.

“The betting is that the left of center government there, left of center party, will probably come in. So left of center in Korea means more nationalism… more kind of accommodating to North Korea, a little less willing to follow our lead, so there are going to be issues there as we going forward. But we’re going to know in the next 60 days or so,” Hill said.

Secretary of State Rex Tillerson will meet with South Korean leaders next week during his trip to Asia. His other stops include Japan and China. However, as of now, the State Department will not be allowing the traveling press on the secretary of state’s plane, as is customary.

“So it is a little unusual, and the really question is why,” Hill said regarding Tillerson’s decision to leave the press behind. “Is it because the secretary of state doesn’t have enough running room from the White House? Is it the fact that he doesn’t have his team sort of named and put into place? What are the reasons? Or is he just sort of someone who doesn’t like to talk to the press? And if it’s that, I think we have a problem.”