To that high concept there can be no end save victory. in this context, what would roosevelt consider a victory?

Freedom from oppression and the attainment of human rights will be freedom for Roosevelt.

Explanation:

According to Roosevelt, though the fight for freedom against any form of oppression is needed and had to be done, so is the need and importance of the supremacy of the rights of humans. But above all, whatever may be done and thought of, nothing like victory compares to the full attainment of freedom for the people. So, to him, victory will be the absolute attainment of freedom and human rights by the people of America.