The problem, Lee said, is that the U.S. has not been seeing its sanctions through.

“With each major provocation, the temptation to step back and return to negotiations with bigger concessions in tow, that’s been the problem so far. That kind of attitude, trying to get North Korea out of the headlines, has led to premature relaxation of sanctions and North Korea has been getting away with virtually murder,” Lee said.

Pyongyang’s latest missile launch came on the back of several short-range missile tests on Saturday into the sea off its east coast as the U.S. and South Korea conducted annual joint military drills.

The latest missile test was “designed mostly to demonstrate Pyongyang’s opposition to joint military exercises currently being conducted by the U.S. and South Korea,” Scott Seaman, director for Asia at consultancy Eurasia Group, said in a note.

“It might also have been planned to occur when Pyongyang assumes that Trump’s team is preoccupied with Hurricane Harvey,” he added.