Final answer:
President Jackson vetoed the bill to subsidize the Maysville Road in Kentucky because he believed it was beyond the scope of the federal government's powers. Democrats, including Jackson, believed in strict construction of the Constitution and limited federal power.
Step-by-step explanation:
President Jackson vetoed a bill to subsidize the constant construction of the Maysville Road in Kentucky because he believed it was beyond the scope of the powers granted to the federal government. The Democrats, to which Jackson belonged, believed in a strong central government but with most decisions left to the states. They interpreted the Constitution with strict construction, meaning that they only believed in granting federal power if it was explicitly stated in the Constitution. Funding for projects like the Maysville Road was seen as a state responsibility, not a federal one.