No clear definition of sustainable development exists to guide politicians in solving challenges at the global or regional levels. Rather, the concept's use has increasingly reflected socially desirable attributes of solutions to local- and project-level problems, but these ignore the global challenges that the concept was meant to address. We return to the original definition of sustainable development used in the Brundtland Report and suggest an assessment method to determine whether countries currently meet the threshold values of four equally important primary dimensions: safeguarding long-term ecological sustainability, satisfying basic needs, and promoting intragenerational and intergenerational equity. We also define indicators and threshold values for each of these dimensions; in addition, we show how 167 countries compare in meeting these threshold values. Currently, no country meets all four thresholds. Even so, we propose that, with the use of technology and behavioural changes, it will be possible to reach the threshold values by 2030.