May national law be used to escape international treaty obligations by state

No, national law may not be used to escape international treaty obligations by a state. International treaties are binding agreements between states and must be upheld by all parties involved. States are expected to abide by their treaty obligations and can be held accountable for any violations. National laws must be consistent with international treaties, and if there is a conflict between the two, the treaty will take precedence. States cannot invoke their national laws to avoid their responsibilities under international law.