Broadened: Broadening refers to making something wider or more extensive. In this case, it would mean increasing the scope of federal government powers.
Enhanced: Enhancing means improving or strengthening something. When the powers of the federal government are enhanced, they are made stronger or more effective.
Amplified: Amplifying means increasing in intensity or volume. If we amplify the powers of the federal government over commerce, we give them greater control and influence in regulating commercial activities.