How does the idea of "checks and balances" contribute to american democracy?

Checks and balances allow for a more democratic system as no single person or even branch of government has the opportunity to take complete control of the government. For example, Congress can overturn a presidential veto with a 2/3 majority re-vote in both the Senate and House of Representatives. This prevents the president from vetoing everything, only advancing his personal agenda.

both are true, the congress does have the power to create banks, even if this power is not specifically described in the constitution, since there is nothing restricting it and there is power given to the congress to make "all laws which shall be necessary and proper". maryland was not allowed to tax a branch of the national bank operating there, and the supreme court decided that no state could. both of these topics were discussed in a decision of the mcculloch v. maryland case in 1819.