Worry about US-SKorea alliance grows before Trump-Kim summit

FILE - In this Sept. 18, 2017, file photo provided by South Korea Defense Ministry, U.S. Air Force B-1B bombers, F-35B stealth fighter jets and South Korean F-15K fighter jets fly over the Korean Peninsula during joint drills. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (South Korea Defense Ministry via AP, File)
FILE - In this Sept. 18, 2017, file photo provided by South Korea Defense Ministry, U.S. Air Force B-1B bombers, F-35B stealth fighter jets and South Korean F-15K fighter jets fly over the Korean Peninsula during joint drills. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (South Korea Defense Ministry via AP, File)
FILE - In this Nov. 7, 2017, file photo, U.S. President Donald Trump, accompanied by United States Forces Korea Commander Gen. Vincent Brooks, center left, attends an operational briefing at the eighth Army Operational Command Center at Camp Humphreys in Pyeongtaek, South Korea. Ahead of the second summit between Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (AP Photo/Andrew Harnik, File)
FILE - In this Nov. 7, 2017, file photo, U.S. President Donald Trump, accompanied by United States Forces Korea Commander Gen. Vincent Brooks, center left, attends an operational briefing at the eighth Army Operational Command Center at Camp Humphreys in Pyeongtaek, South Korea. Ahead of the second summit between Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (AP Photo/Andrew Harnik, File)
FILE - In this March 25, 2015, file photo, U.S. Army soldiers from the 25th Infantry Division's 2nd Stryker Brigade Combat Team and South Korean soldiers take their position during a demonstration of the combined arms live-fire exercise as a part of the annual joint military exercise Foal Eagle between South Korea and the United States at the Rodriquez Multi-Purpose Range Complex in Pocheon, South Korea. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (AP Photo/Lee Jin-man, File)
FILE - In this March 25, 2015, file photo, U.S. Army soldiers from the 25th Infantry Division's 2nd Stryker Brigade Combat Team and South Korean soldiers take their position during a demonstration of the combined arms live-fire exercise as a part of the annual joint military exercise Foal Eagle between South Korea and the United States at the Rodriquez Multi-Purpose Range Complex in Pocheon, South Korea. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (AP Photo/Lee Jin-man, File)
FILE - In this Dec. 10, 2015, file photo, U.S. and South Korean army soldiers pose on a floating bridge on the Hantan river after a river crossing operation, part of an annual joint military exercise between South Korea and the United States in Yeoncheon, south of the demilitarized zone that divides the two Koreas, South Korea. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (AP Photo/Ahn Young-joon, File)
FILE - In this Dec. 10, 2015, file photo, U.S. and South Korean army soldiers pose on a floating bridge on the Hantan river after a river crossing operation, part of an annual joint military exercise between South Korea and the United States in Yeoncheon, south of the demilitarized zone that divides the two Koreas, South Korea. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (AP Photo/Ahn Young-joon, File)
FILE - In this Nov. 12, 2017, file photo provided by South Korea Defense Ministry, three U.S. aircraft carriers USS Nimitz, left top, USS Ronald Reagan, left center, and USS Theodore Roosevelt, left bottom, participate with other U.S. and South Korean navy ships during the joint naval exercises between the United States and South Korea in waters off South Korea's eastern coast in South Korea. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (South Korea Defense Ministry via AP, File)
FILE - In this Nov. 12, 2017, file photo provided by South Korea Defense Ministry, three U.S. aircraft carriers USS Nimitz, left top, USS Ronald Reagan, left center, and USS Theodore Roosevelt, left bottom, participate with other U.S. and South Korean navy ships during the joint naval exercises between the United States and South Korea in waters off South Korea's eastern coast in South Korea. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (South Korea Defense Ministry via AP, File)
FILE - In this March 12, 2016, file photo, Marines of the U.S., left, and South Korea, wearing blue headbands on their helmets, take positions after landing on a beach during the joint military combined amphibious exercise, called Ssangyong, part of the Key Resolve and Foal Eagle military exercises, in Pohang, South Korea. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (Kim Jun-bum/Yonhap via AP, File)
FILE - In this March 12, 2016, file photo, Marines of the U.S., left, and South Korea, wearing blue headbands on their helmets, take positions after landing on a beach during the joint military combined amphibious exercise, called Ssangyong, part of the Key Resolve and Foal Eagle military exercises, in Pohang, South Korea. Ahead of the second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, some observers say there is an uncertainty over the future of the decades-long military alliance between Washington and Seoul. (Kim Jun-bum/Yonhap via AP, File)