Common Core is what we do. STEM is how we do it.
"The United States has become a global leader, in large part, through the genius and hard work of its scientists, engineers and innovators. Yet today, that position is threatened as comparatively few American students pursue expertise in the fields of science, technology, engineering and mathematics (STEM)—and by an inadequate pipeline of teachers skilled in those subjects. President Obama has set a priority of increasing the number of students and teachers who are proficient in these." - from D.O.E Website