Article: There are several reasons an otherwise valid and agreed upon treaty may be rejected as a binding international agreement, most of which involve problems created at the formation of the treaty.[citation needed] For example, the serial Japan-Korea treaties of 1905, 1907 and 1910 were protested; and they were confirmed as "already null and void" in the 1965 Treaty on Basic Relations between Japan and the Republic of Korea.

Question: An otherwise valid and agreed upon treaty may be rejected as what for several reasons most of which involve problems created at the formation of a treaty?
a binding international agreement