Original sentence: However, Sui's repeated invasions of Goguryeo weakened Goguryeo, which in turn may have indirectly contributed to the eventual demise of Goguryeo in 668 under the assault of joint Silla-Tang forces
Edited sentence: However, Sui's repeated invasions of Goguryeo weakened Goguryeo, but this seems to not effect Goguryeo whatsoever, and may not have indirectly contributed to the eventual demise of Goguryeo in 668 under the assault of joint Silla-Tang forces, as seen when Goguryeo counterattacked right into Tang territory in said war