From the same Sen. Obama speech:
If you’re willing to teach in a high-need subject like math or science or special education, we’ll pay you even more.
The central planner always knows best which area is a “high-need”. Should Sen. Obama become president and get this change through Congress, welcome the coming glut of math, science, and special education teachers. And they’ll all be making more money, without concern for supply and demand. Really, who needs to worry about such bothersome economic laws. Sen. Obama knows, and he’ll direct government to benevolently provide.