Who can prevent the President of the United States from controlling the Supreme Court by blocking appointments to the bench?

The President nominates possible Supreme Court Justices, but it is the Constitutionally-required job of the Senate to approve or block the nomination. This is part of the "Checks and Balances" of the government.

labor leaders and organizations had the power to demand it.

explanation:

workers got a five-day workweek because the bcea protects and respect the rights of the employees. labor leaders and other groups demanded it.

an economic reason that the south needed a reconstruction plan is that plantations, factories, and other businesses were destroyed during the war.