With a U.S. president facing the prospect of his party being trounced in midterm elections and a North Korean leader eager for a coming out party on the global stage, what can Japan expect from Tuesday's historic summit? The nightmare scenario: a compromise just good enough for both sides but glaringly lacking for Japan.

Just days ahead of the summit between U.S. President Donald Trump and North Korean leader Kim Jong Un, the upbeat atmosphere surrounding the meeting stands in stark contrast to the nervousness in Tokyo.

"The biggest nightmare for Japan is that Kim declares his intention to relinquish the intercontinental ballistic missiles that he quickly developed last year and Trump simply hails the offer as 'great,' making no further demands," said Matake Kamiya, a professor of international politics at the National Defense Academy.